The Water Thief

By Ben Bova

Illustrations by Michael Carroll

         “This is serious, Mase,” said Drake Callahan, his brow creasing as he struggled to control his anger. “Water is precious and you know it.”

         Fourteen-year-old Mason Callahan thought about turning off both his hearing aids but decided not to because (a) it would be wrong and (b) his father would see him doing it and get even madder at him.

         “We’re not wasting water, Dad,” he said, with a glance at his little sister, Mariah. She looked kind of scared, her eyes big and solemn and riveted on their father’s stern face.

         The three of them were in Mase’s cluttered bedroom, father standing by the entryway with his arms folded angrily across his chest while Mase hunkered down on the floor and scuffed one soft-booted toe on the lucky yellow rock he’d found on an excursion outside. Mariah was sitting on a cleared spot on Mase’s bed. For a moment there was absolute silence in the cramped little room, except for the sighing of a gentle Martian breeze wafting past the window of their habitation module.

         “Mase, you’re the older, that’s why I’m talking mainly to you. Or maybe I should corral your buddy Tregon.”

         “Dad, nobody’s wasting water! Not me, not Mariah, and not Treg.”

         Drake unfolded his arms and scratched at his short-cropped dark hair. “Well, the water monitors show that we’ve exceeded our allotment for the past three months straight. I’ve checked the logs and there’s no mistake about it. We’ve gone over our fair share. Not seriously over, I admit, but somebody’s using more water than he should have and it’s getting a little worse each month. I want it to stop. Rules are rules.”

         “Yeah, sure, I know,” said Mason.

         “This is Mars, kids,” Drake said sternly. “I know it’s home to you, but it’s still a dangerous world in many ways. We have to be very careful about how much water we use. Lives could depend on it!”

         “But we’ve got plenty of water, don’t we Dad? I mean, there’s an ocean of permafrost underneath us, isn’t there?”

         “Yes, but it takes energy to melt that ice and make drinkable water for everyone here. We all agreed to the water allotments, and we’ve got to stick to them.”

         “We are,” Mason insisted.

         “Somebody is using more water than he should,” Drake said darkly. “It’s got to stop.”

         He turned abruptly and left the room.

         Mason looked at his sister. “I’m not wasting water,” he muttered.

         “Neither am I,” said eleven-year-old Mariah.

         “Then who is?”

         “Tregon,” she answered, without an eyeblink of hesitation. “This must be one of his stupid tricks.”

*

         “Me?” Tregon looked genuinely surprised. “I’m not using up your water. You know that.”

         The two boys looked a lot alike. Both were the same age, both had dark unruly hair, both wore funky t-shirts and rumpled jeans. Tregon was a little more than ten centimeters taller than Mason, but so slender that he looked almost frail. Mason’s eyes were lighter than Tregon’s dark Hispanic ones.

         “Well,” Mason said slowly, “if I’m not wasting water, and you’re not, and my dippy little sister isn’t, then who is?”

         Tregon grinned crookedly. “Let’s find out.”

         “How?”

         “Simple. We turn EMMA into a detective.”

*

         Mason fidgeted uneasily at the doorway of the workshop as he looked up and down the corridor, watching out for any approaching adults. It was mid-afternoon and everybody was at their jobs, so the corridor was empty. Still, Mason searched both ways, feeling more and more nervous with each passing second.

         “Aren’t you finished yet?” he hissed at Tregon.

         His buddy was sitting cross-legged on the workbench, his head inside the humanoid robot’s open back panel.

         “Almost,” Tregon muttered.

         “Well, hurry it up; it’s almost time for the afternoon shift to end. Everybody’ll be coming through this corridor and they’re gonna wonder what you’re doing with EMMA.”

         “What we’re doing,” Tregon corrected, with a chuckle.

         “Come on,” Mason urged.

         “Okay,” said Tregon. “Finished. All I have to do is replace the panel.”

         He clicked the plastic panel into place, then picked up the remote controller and thumbed its power key. EMMA stirred to life, its round camera eyes began to glow, a slight whirring sound buzzed from deep inside its chest cavity. The little robot was slightly shorter than Mason, and only shoulder high to Tregon.

         Tregon said in the deepest voice he could manage, “EMMA, review your new program, please.”

        The robot turned on its wheels to face Tregon and said, “I am to monitor water usage in the Callahan residence. From midnight to 0600 hours I am to check all water pipes in the residence for leakage.”

         Tregon nodded. “Right. Good.”

         “Let’s get back to my place,” Mason said, feeling relieved.

         As the two boys hustled down the corridor, with EMMA trailing slightly behind them, Tregon said, “My bet’s on Apollo.”

         “Huh?”

         Grinning, Tregon explained, “That’s one smart cat you’ve got, Mase. I bet he figured out how to turn on the tap at your kitchen sink. He’s your water thief.”

         Mason shook his head in silent disbelief.

*

         Two days later, Tregon admitted, “Well, it’s not Apollo.”

         “And it’s not Sputnik, either,” Mason said glumly.

         The boys were in Tregon’s bedroom, watching the speeded-up video that EMMA had recorded during the previous two nights. Apollo napped in Mariah’s room, then got up, prowled, sniffed here and there, lapped at his own water dish, then napped again – all in blurringly fast motion. Despite his growing worry, Mason had to laugh at the video. Apollo was all over the apartment, flitting away madly, while the dog Sputnik slept blissfully, unmoving except for a twitch of his tail or an occasional scratch with his hind leg.

         “And there are no leaks in your pipes,” Tregon added. “At least, none that EMMA could find.”

         Mason shook his head. “Dad’s gone over all the pipes three or four times. He’s even had a couple of guys from maintenance check 'em out. No leaks.”

         “But if you’re still using more water than you’re supposed to,” Tregon said, “then there must be a leak that they haven’t found.”

         “Unless somebody’s deliberately stealing water from our pipe,” said Mason. He hesitated a heartbeat, then asked, “Look, Treg, I’ve gotta ask you…is it you? Are you sneaking water from our place?”

         Tregon looked totally surprised. “Me! No way!”

         “Sis thinks it’s one of your tricks, and she’s got Dad halfway thinking she might be right.”

         “It’s not me,” Tregon said, utterly serious.

         “Okay,” said Mason. “Then we’ve got to find out who it is, before Dad goes ballistic.”

         “He’s that mad?”

         “I heard him telling Mom that it might be better if they stop letting you visit our place.”

         For one of the rare times in his life, Tregon looked sad. “He really said that?”

         “He’s pretty sore. I think it’s not knowing how we’re losing the water that’s really got him spooled up. Dad’s a scientist, y’know, and the worst thing that can happen to him is coming across a puzzle he can’t solve.”

         Tregon’s cocky grin returned. “Then we’ll have to solve it for him.”

*

         “What are you two up to now?” Mariah asked the instant she stepped into Mase’s bedroom.

         Mason and Tregon were sitting on the floor with their backs against the bed. On the floor in front of them was an open laptop computer with a hologram shimmering faintly above it.

         “Go away,” Mason snapped. “Go to your own room.”

         “Oh no,” said Mariah, with her nose in the air. “You two are up to something, I can tell.”

         “We need some privacy, Mariah,” Tregon said.

         “Why? What’re you doing?” Mariah scampered across the messy room toward the two boys. Tregon quickly turned off the hologram.

         “Privacy,” Mason said firmly.

         “No,” said Mariah, planting her fists on her hips stubbornly.

         Mason growled, “If you don’t get out of here – ”

         Tregon interrupted, “What we’re doing is top secret, Mariah. If you want to know about it, you’ve got to swear that you won’t tell anybody.”

         Mariah hesitated. “You mean, like, not even Mom or Dad?”

         “Not even anybody,” Tregon said, with great seriousness.

         “Look, Sis,” Mason said, “Dad’s blaming Tregon for our water shortage – ”

         “He’s probably right,” Mariah sniffed.

         Mason gritted his teeth, then continued, “So we’re trying to figure out what’s really going on, and who’s stealing our water.”

         “So what’s so secret about that?” Mariah asked.

         “We can’t tell you until you promise not to tell anybody,” Tregon said.

         Mariah thought it over for all of five seconds, then said, “Okay, I promise.”

         “You’ve got to swear,” Mason insisted.

         “Swear?”

         With a crafty smile snaking across his lips, Tregon said, “You’ve got to swear that if you don’t keep what we’re doing an absolute, totally cosmic secret, Mase and I can take your doll collection outside and bury them all in a crater.”

         “Bury my dolls!” Mariah looked horrified.

         “That’s the deal,” said Tregon. “If you tell anybody what we’re doing, your dolls sleep in the sand.”

         Mariah stood in front of the two boys, her face showing the struggle going on inside her. She frowned, she grimaced, she grumbled to herself.

         At last she said, “Oh, all right. I swear I won’t tell anybody what you’re doing.” And she plopped herself down on the floor next to her brother.

         “If you break your promise,” Tregon said, “your dolls…” He drew a finger across his throat.

         Mariah nodded solemnly. Mason turned away slightly so she wouldn’t see him grinning.

         “Okay,” Mariah said eagerly, “so what’s the big secret?”

         “We’ve tapped into the base’s computer files,” said Tregon, lighting up the hologram again.

         “You hacked the central computer?”

         “Just the water system,” Mason said, pointing at the bewildering set of colored lines criss-crossing in three dimensions.

         “That’s the base’s whole water system?” Mariah asked, peering at the schematic hovering above the laptop’s keyboard.

         “Most of it,” said Mason. “We couldn’t get the section where the water pipes go out to the reactor.”

         “Everything about the reactor is kept under special safeguards,” Tregon said. “I could hack into the files for the rest of the water system, but not the part that involves the reactor; they’re under special security codes.”

         “People worry about radiation because the reactor’s nuclear?” Mariah asked.

         “It’s not a bomb,” Mason grumbled. “It can’t explode.”

         Mariah looked as if she didn’t entirely believe that. Then she asked, “Why do the water pipes go out to the reactor, anyway?”

         Mason answered, “They need water to cool the reactor.”

         “And they use the waste heat from the reactor to help melt the permafrost, underground,” Tregon added.

         “It’s a pretty cool system,” she said.

         Nodding, Mason replied, “Except that there’s a leak someplace, and we’re getting blamed for it.”

         Tracing a finger along one of the red lines on the holographic display, Tregon said, “There aren’t any leaks. If there were, they’d show up on this schematic. The maintenance people check those pipes all the time. They even have robots crawling inside the pipes to check ‘em. No leaks.”

         “Inside the pipes?” Mariah asked.

         “Yup,” said Tregon.

         Mason sighed. “Somebody’s taking more water out of the system than he’s supposed to.”

         “On purpose?” Mariah’s voice squeaking slightly.

         “On purpose,” Mason agreed.

         “Which puts us right back where we started,” said Tregon. “Missing water and no clue about how, why, or who’s doing it.”

         Mason nodded as Tregon went on, “And whoever’s doing it, he’s taking the water from the section of the pipes that leads into your module.”

         “He’s stealing our water!” Mason said, starting to feel angry.

         “What makes you think it’s a he?” Mariah asked. “It could be a girl, you know.”

         “A girl? Give me a break!” Mason looked disgusted by the idea.

         “Boy or girl, somebody’s taking water from the pipe leading into your module,” Tregon said.

         “But the maintenance robots haven’t found any leaks,” said Mariah.

         Mason scratched his head, very much the way his father often did. “Wait a minute. The maintenance robots are programmed to look for leaks, right?”

         “Right,” said Tregon and Mariah in unison.

         “But they’re not programmed to look for a pipe that somebody might’ve added to the system.”

         “Added?”

         “Our thief,” said Mason, “must’ve connected a pipe to the main line that supplies our module. He takes some of our water away with the pipe he’s tacked on to our line.”

         Tregon shook his head. “Naw. That would show up as a leak. The maintenance robots would spot it.”

         “Not if the thief’s pipe has a valve on its end,” Mason said, grinning at them both. “A valve that he only opens when he wants to steal some of our water. A valve that he keeps closed when the maintenance robots are checking our section of pipe.”

         “You think?” Mariah asked, her green eyes wide.

         Tregon looked intrigued. “Then the thief knows how to get into the water system.”

         “And add at least one pipe without letting anybody know it’s there,” Mason said.

         “And he must know when the maintenance robots are coming through,” Tregon added.

         “It’s got to be somebody who knows the system backwards and forwards,” Mason agreed.

         “Who could it be?” Mariah asked, almost breathless with excitement. “And why is he stealing our water?”

         Mason noticed she no longer thought the thief might be a girl.

*

         “Why can’t I go?” Mariah asked.

         “You stay here,” Mason told his sister, “and warn us if Mom or Dad shows up.”

         Mariah, Mason and Tregon were in the tiny kitchen of the Callahans’ module. Mason had unscrewed the panel under the sink and laid it on the floor. Tregon was sitting crosslegged beside it, squinting at the tiny screen of his wristphone.

         “Besides,” Mason went on, “you’re too big for this job. You’ll get stuck down there.”

         Mariah frowned at her brother, but said nothing. She thought of all the times she had twitted Mase about being taller than he. Now Mason was getting even.

         “Maybe I oughtta go,” Tregon said. “I’m the skinniest.”

         “I’ll do it,” Mason said firmly. “You watch the schematic and follow my beacon.” He picked the tiny disc of the radio beacon off the floor and tucked it into the pocket of his cutoffs.

         Tregon nodded. “I can see it on the screen now.”

         Mariah bent over Tregon’s shoulder and saw the hologram of colored lines that represented the system of water pipes. A tiny red dot was flashing away in one corner of the display.

         “Okay,” Mason said, taking in a deep breath. “Here I go.”

         “Be careful,” Mariah whispered to him.

         “Sure.”

         Mason slithered beneath the sink and crawled on his belly into the darkness beyond the opening in wall, groping along with his arms out in front of him.

         Bringing one hand close to his mouth he muttered into his wristphone, “Boy, it’s cramped in here.”

         He heard Tregon’s voice, “You’re following the pipe that carries water into your module. See any pipes that shouldn’t be there?”

         “Not yet.” Mason inched along the narrowing passageway, his flashlight in his right hand. “Just the one pipe.”

         “It bends to the left just a meter or so in front of where you are,” Tregon said.

         “Yeah, I see the bend.”

         “And then it goes down to join the main pipe.”

         Mason was sweating. It’s hot down here, he said to himself. I thought it’d be cold.

         He felt the pipe. It was cold to his touch. He could hear water gurgling.

         “Hey!” he shouted. “Water’s flowing through the pipe!”

         Tregon’s voice answered, “Your sister’s taking a drink.”

         “Oh. I thought somebody was stealing our water.”

         “Naw. Just Mariah.”

         The cramped tunnel seemed to end up ahead. Mason saw that the pipe elbowed downward, into a dark shaft.

         “I’ve reached the spot where it goes down,” he said.

         “Right. I can see the beacon. Can you get down that shaft?”

         “It’s pretty narrow,” Mason said, peering down into the blackness. His flashlight’s beam seemed to be swallowed up by the dark.

         “It only goes down three meters,” Tregon said. “Then the pipe joins the main one.”

         Mason leaned over the edge of the shaft and played his light along the pipe. “I can see where it joins the main pipe.”

         “Is anything else there?” Tregon asked. “Another pipe attached to yours. Or maybe to the main?”

         Mason edged further over the lip of the shaft. “No,” he reported. “No other pipe. Just the one from our kitchen, connected to the main.”

         “Blast,” Tregon muttered. “Nobody’s tapped into your pipe.”

         “Guess not,” said Mason, wriggling back from the edge of the shaft.

         “Then who’s stealing your water? And how’s he doing it?”

         “I’ve got another question for you,” Mason said, sweating even harder than before.

         “Another question? What?”

         “How do I get out of here? I’m stuck.”

         “Stuck?”

         “I’m trying to back out, but I can’t. Something’s got me hung up.” Mason tried to keep the fear out of his voice, but he knew he sounded shaky, kind of scared.

         Without hesitation Tregon answered, “Hang in there, Mase. I’ll come and get you.”

         “I am hanging in here! It’s all I can do!”

         Back in the kitchen Mariah said, “Tregon! Wait! Let me go after him.”

         But Tregon was already crawling under the sink. “I’m slimmer,” he called back to Mariah. “I’ll get him.”

         “Here,” she yelled to him. “Take this cord with you. You might need it.”

         Tregon stopped only long enough to grasp the coil of electrical cord that Mariah was holding out to him.

         “Where’d you get this?” he wondered.

         “From Dad’s tool box. I thought it might come in handy.”

         “Good thinking,” Tregon said, clutching the coil in one hand. Then he slithered forward, after Mason.

         He heard Mase’s voice in his wristcom. “I think my shirt’s hooked on something. Like a nail or a screw or something.”

         “Okay, okay,” Tregon said, feeling excited and a little afraid. What if I can’t get him out? he asked himself. What if his parents come home and he’s still stuck?

         It was dark in the tunnel, and Tregon hadn’t thought to bring a light. But at last his hand bumped into something that felt like Mase’s softbooted foot.

         “That you, Mase?”

         “Yeah.”

         “Can you turn around?”

         “No room!”

         “Okay, okay.” As he fumbled in the darkness Tregon said, “I’m gonna tie this cord around your ankle, then we’ll drag you out.”

         “We?”

         “Your sister and me. We ought to be able to haul you free of whatever’s got you caught up.”

         “I hope so,” Mason said.

         Tregon knotted the cord around Mason’s ankle, then started slithering backwards along the tunnel. The walls and floor felt gritty, dusty, but smooth enough. Nothing sticking out to get caught on.

         Finally he was under the sink. Breathing a sigh of relief, Tregon crawled out, the cord firmly grasped in his right hand.

         Before he could get to his feet, though, he saw that Mason’s father was standing in the middle of the kitchen, fists on his hips. Mariah stood beside him. She looked scared.

         Drake Callahan looked furious.

*

         “I’ve never seen your father look so spooled up,” Tregon said, with genuine awe in his voice. “I thought he was gonna explode.”

         Mason still felt guilty about the whole thing, especially about getting himself hung up on a projecting bolt in the tunnel. His Dad had hauled him free, but it had torn Mase’s shirt and rubbed a raw bruise along his chest.

         “I can’t stay long,” he said. “Dad doesn’t want me to see you. If he finds out I’m here…” Mase’s voice trailed off.

         The boys were in the maintenance locker, out at the far end of the settlement where the maintenance crews stored most of their equipment.

         “He won’t,” Tregon said lightly. “Nobody’d think of looking for us out here.”

         “But if he does…”

         Tregon tapped his friend’s shoulder. “He can’t possibly get any madder at you than he is now, can he?”

         Despite his fears, Mason broke into a grin. “No, I sure don’t think so.”

         Tregon grinned back at him. “So let’s find a breathing mask and an air tank.”

         “I don’t think we ought to do this,” Mason muttered.

         “Come on,” Tregon coaxed. “We had a special class on working through crawl spaces, remember?”

         “Yeah, but still…”

         “Hey, it was your idea. Remember?”

         Mason had to admit that Tregon was right. But he hadn’t meant it seriously. He’d just been thinking out loud. If we can’t find the reason for the water loss from looking at the outside of the pipes, he had figured, then the only thing left to do is take a look inside the pipes.

         “I didn’t mean that we should really do it,” he said.

         Tregon reached for one of the breathing masks hanging in a row along the wall. “Hey, it’s a good idea, Mase. A logical idea.”

         “A crazy idea.”

         “Not to me.”

         Mason shook his head, but helped Tregon lift one of the heavy air tanks from the cradle on which it rested.

         “If it’s my idea,” he said, holding the green tank in both hands, “then I should go.”

         “With those big shoulders of yours?” Tregon kidded. “You got yourself stuck under your own sink. You’d never get through the water pipes.”

         “Neither will you. Not the smaller ones, anyway.”

         “We’ll see.”

         Reluctantly, Mason helped Tregon slip his arms through the tank’s shoulder straps and buckle the waist cinch around his slim middle. Tregon pulled the breathing mask over his face.

         “Check the air flow,” he said, his voice muffled by the mask.

         Mason looked at the little gauge on the tanks. Air was flowing.

         “You’re okay,” he said.

         Tregon nodded and the two boys stepped past shelves of more equipment, to the very end of the structure. An airlock was set into the end of the wall. Mason could see the dusty red surface of Mars through its thick window. The normally clear air was a dark sickly yellowish color, with clouds billowing up far out at the horizon.

         “Looks like a dust storm building up out there,” he said.

         “Good,” said Tregon. “That’ll keep everybody’s attention away from us.”

         There was a big hatch set into the floor, with a wheel sticking up from its heavy dome of steel. The boys had checked the water system’s schematics: there were no alarms attached to the maintenance hatches. At least, they hadn’t found any in the schematics.

         Half expecting an alarm to start hooting, Mason helped Tregon turn the wheel that unsealed the hatch. No alarms. Only a slight squeaking sound from the wheel itself. It took both of them to lift the massive hatch and swing it back.

         Mason couldn’t see Tregon’s face inside the breathing mask. But his friend stuck out his hand and said, “Here I go.”

         But Mason said, “Wait.”

         He trotted back to the shelves and searched quickly until he found a spool of buckyball cable. Wire-thin, the material was much stronger than steel. Carrying it back to Tregon, Mason knelt down and tied one end of the light weight cable around Tregon’s left ankle.

         “In case you need some help getting back.”

         “The voice of experience.” Even though Tregon’s face was hidden by the breathing mask, Mason could hear the grin in his voice.

         Mason nodded. Then he grabbed Tregon’s hand. “Good luck, bud.”

         Tregon slapped Mason’s shoulder lightly, then said, “Here I go.”

         He climbed down the ladder and disappeared from Mason’s sight.

*

         The pipe was narrow, barely wide enough for Tregon to slither along inside it. And the water was cold. Tregon could feel his air tank bumping against the top of the pipe while he “walked” on his fingertips and toes through the icy water. This is cool, he thought. Kind of like swimming.

         Mason had attached a lamp to a sweat band and snugged it over his head, so wherever he looked there was enough light to see the plastic insides of the main water pipe. The water flowed smoothly, gently; Tregon could push himself through it without all that much trouble. Every now and then he heard a gurgling sound and saw bubbles drifting past him. Somebody must have turned on a tap someplace, he thought, and a valve opened to allow the water to flow.

         “How’re you doing?” Mason’s voice sounded thin, almost feeble, in the communicator built into the breathing mask.

         “Okay,” Tregon answered, surprised that it took so much effort to say anything. “It’s pretty cramped in here. And cold.”

         “You want to come back?”

         “Not yet.”

         Tregon had memorized the layout of the pipes. His aim was to slither all the way down to the point where the access pipe from Mason’s module connected with the main. There has to be another pipe attached in here somewhere, he said to himself. A rogue pipe that the thief snuck into the system. Has to be!

         But there wasn’t. He saw seams in the pipe, where sections had been cemented together. Some of the seams had a thin, slimy-looking coating on them, most didn’t. He saw valves and joints where other pipes tapped off the main. Nothing that he didn’t remember being in the schematic. Nothing that didn’t belong where it was. Nothing that indicated somebody was stealing water.

         Why would anybody want to steal water, anyway? Tregon asked himself. If you need more water you ask the water board. They hardly ever turn anybody down.

         There it was. The pipe that led up to the Callahans’ module.

         “I see your access pipe,” he said into the mask’s microphone.

         “Anything else?”

         “I counted six pipes between the place where I went in and yours.”

         A pause. Then Mason’s voice, sounding disappointed, “Six. Check. That’s what the schematic shows.”

         “No extra pipes.”

         “No thief.”

         Tregon shook his head. He could feel his long hair sloshing around in the water.

         “Guess I might as well come back,” he said, feeling disappointed.

         “Guess so.” Mason sounded just as glum.

         It was too tight to turn around inside the pipe, so Tregon started to back out. He felt the air tank scraping along the pipe’s curved plastic wall. Slowly, carefully, he edged backwards along the length of the pipe. I won’t get stuck in here, he thought. I got in okay, I’ll get out okay. But he was still glad that Mase had tied that bucky-ball cable to his ankle.

         At last he climbed up and out of the pipe, dripping wet, and yanked off his breathing mask. Mason started to help him slip out of the air tank’s shoulder straps.

         “Hey! What’re you kids doing in here?”

         They looked up and saw one of the maintenance technicians heading toward them, a deep frown lining his face.

         Tregon and Mason looked at each other and said, “Uh-oh.”

*

         They had wrapped a blanket around Tregon, but still his cutoffs were dripping water onto the floor as he and Mason stood before the maintenance chief’s desk.

         “Inside the main water pipe?” The maintenance chief clearly was having a hard time believing it. He was one of the older men in the Mars settlement: his hair was silver gray, but he still looked trim: his coveralls didn’t bulge in the middle, the way some of the other elders’ did.

         Standing beside his friend, Mason said, “We were trying to find out who’s stealing water.” Then he added, “Sir.”

         The maintenance tech pointed to the breathing mask and air tank. “They stole this equipment. And damaged it.”

         “We borrowed it,” Mason said quickly.

         “And it’s not damaged,” said Tregon.

         The maintenance chief got up from his desk and walked over to the equipment. He bent down and lifted the air tank.

         “Maybe it’s not really damaged,” he muttered, looking the tank over carefully. “But what’s this crud smeared on it?”

         Mason saw a grayish slimy-looking goo sticking to one side of the tank.

         “That’s the stuff that was on some of the seals in the piping,” Tregon said. “The tank must’ve scraped some of it off when I went through.”

         The chief touched the goo with a fingertip. And frowned. “Glop,” he said, reaching for a tissue to wipe his finger. Turning to the technician, he asked, “What is this stuff?”

         The tech shrugged. “Darned if I know.”

         “Some kind of sealant?” the chief mused.

         The technician shook his head. “We don’t use any sealant inside the piping.”

         “Then what on earth is it?” the chief demanded.

*

         Drake Callahan scowled at the boys. He was sitting at his desk, his son and Tregon standing at attention in front of it. The maintenance chief had marched Mason and Tregon to Callahan’s laboratory as soon as he had determined that no damage had been done to the water system.

         Mason’s father sat there for many long, silent moments. Still clutching the blanket around his shoulders, Tregon wondered when the explosion would come. He thought he saw the beginnings of a smile on Dr. Callahan’s face, but he figured that was just wishful thinking. He and Mase were in for trouble, real trouble, and he knew it.

         At last Dr. Callahan said slowly, “That was an incredibly stupid thing you two did.”

         Mason glanced at Tregon, then replied, “We were trying to find the water thief, Dad.”

         “Were you.” The way Dr. Callahan said it, it wasn’t a question.

         “Yessir,” said Tregon.

         “You might have been seriously hurt. You might have damaged our water system. Did that ever occur to either of you?”

         “We didn’t get hurt and we didn’t damage the pipes,” Mason said.

         Dr. Callahan started to reply, hesitated, then said only, “That’s true.”

         “We were just trying to help,” Tregon said.

         “We wanted to find the water thief,” Mason repeated.

         “And did you?” Dr. Callahan asked darkly.

         Both boys shook their heads.

         “No, we didn’t,” Mason admitted.

         “Wrong.”

         “I know it was wrong, but – ”

         Dr. Callahan was definitely smiling, Tregon realized.

         “I don’t mean that what you did was wrong – although it was,” said Mason’s father. “What I meant was that you did find the water thief.”

         “Huh?”

         “That gray slime on the air tank. Do you know what it is?”

         “Glop,” said Tregon.

         “Bacteria,” said Dr. Callahan. “A colony of underground bacteria. Martian bacteria.”

         “Martian?” Mason gasped.

         With a nod, Dr. Callahan said, “We think so. The biologists are testing them to find out for sure.”

         “Martian bacteria,” Tregon said, sounding awed.

         “We’ve know that there are colonies of bacteria living deep underground, ‘way down below the surface,” Dr. Callahan said. “They’re similar to bacteria types on Earth that the biologists call SLiMES: subsurface lithotropic microscopic ecosystems.”

         “Lithotropic means ‘rock loving,’ doesn’t it?” Mason asked.

         “Right,” his father answered. “They eat rock.”

         “They look slimy,” said Tregon. “That’s for sure.”

         “We’ve found Martian SLiMES living kilometers deep, below the permafrost layer,” Dr. Callahan went on. “We don’t know if what you found in the water pipe is the same species or a different type.”

         “Could they be Earth bacteria that’ve made themselves at home here on Mars?” Mason asked.

         His father replied, “I doubt it. But whatever they are, they must have sensed the liquid water in our pipes and infiltrated the pipes to take advantage of it.”

         “So there was a water thief, after all,” Tregon said.

         “They wormed their way into the pipe, through the seals between sections of piping,” Dr. Callahan explained. “Maybe there were pinhole leaks in the pipe and that’s how they found the water.”

         “You mean we’ve been swallowing Martian bugs in our drinking water?” Mason asked, feeling alarmed.

         Dr. Callahan shook his head. “No. Our drinking water is filtered.”

         “But we’ll have to figure out a way to keep them out of the pipes,” Tregon said. “Otherwise they’ll take all our water, sooner or later.”

         Dr. Callahan laughed. “The biologists will tackle that problem. But they don’t want to drive the bugs away altogether. They want to study them.”

         “We actually helped the biologists?” Mason asked.

         His father’s stern expression came back. “Don’t think you’re going to be congratulated. What you did was dangerous. Foolish and dangerous. You’re not heroes.”

         “Maybe not,” Tregon said, beaming his biggest grin. “But I’m the first guy ever to go scuba diving on Mars!”

THE END