This is the third installment of "Undersea Prisoner", a science fiction story by pioneering writer Harl Vincent. The story first appeared in the February 1940 issue of Amazing Stories, and was reprinted in the Spring 1971 issue of Science Fiction Adventure Classics.
The story so far:
After being framed for his friend's murder, Richard Burke avoids a prison sentence by volunteering to take part in a dangerous experiment, riding an undersea balloon to a depth of six miles. Burke suspects that the balloon's inventor, Professor Francis Augustine, is the man who framed him. With the aid of another prisoner, Burke is able to trap Augustine with him in the descending balloon. When Augustine regains consciousness, he tells Burke that he welded the iron ballast to the gondola's hull, so that they will be unable to return to the surface. The balloon is more than three miles down when a giant squid attacks it, ripping the gondola from the balloon and swallowing it whole . . .
Monster with a Stomachache
Finally the car lurched to rest with its floor cocked at an angle. Not so bad, though; at least they could stand. They took stock of their bruises and of the bizarre surroundings.
"Hell of a note," grumbled Burke. Out through the port he saw only the swirling green stickiness of the digestive juices of their captor's interior. "Ugh!"
Augustine was blubbering again. "Dick," he whined, "before I die, I must confess. I was the one who killed Van den Broek. I set the police on you. I planted the evidence. Forgive me, Dick."
Forgive? Burke forgot their plight, forgot everything but blind rage. This man would've let him rot in the pen. He'd have sent him to the hot seat if he could. And now this! But rage was futile now.
"Hell of a time to confess!" snarled Burke. "You make me think of a guy who paid his pal fifty bucks he'd owed him for ten years -- just when the boat they were on was torpedoed. Sinking. Shut up your blubbering and tell me where's the gadget you charge the shell with."
"You built a weapon into these things to ward off undersea monsters. What good is it? How does it work?"
The demoralized professor shakily indicated a small control panel. Burke examined it, then yanked the rheostat all the way over. The result was instant and nearly catastrophic. A blinding flash outshone their floods in the green murk outside. The car heaved wildly, smashed him to the floor. Then he came up against the wall under a table.
There were violent upheavals and shudderings.
"The thing's trying to vomit us out," moaned the professor. "And we're stuck in its throat."
Burke could see that this was so. A port faced directly out toward the creature's mouth. The mouth was stretched wide. Through its gaping maw the engineer could see reflected in the glare of their flood lights the rocky rim of the cavern entrance. And the frayed cable ends dangling from above. Then, with a wild lunge, the monster flung out of its lair into the black abyss of the sea.
Clinging to the bolted-down legs of the table, Burke managed to get to his feet. He switched off the floods and saw that the green murk remained alight. The lambent flame that told of intense heat generated by this weapon that had been loosed within the beast. There were momentary flashes of emptiness where the thick green fluid would clear away only to be replaced by rolling whiteness. Steam!
"Hey, Prof!" Burke yelped. "What kind of energy's this?"
No answer. Augustine had fainted. He couldn't take it.
While the car swayed and teetered in the mad flight of the tortured beast, Burke clung to the table and studied the instruments. There was an indicator of horizontal speed and a compass. They were traveling east-northeast at ninety miles an hour! The pressure was decreasing. Which meant they were rising as well! Could this thing travel! Burke shut off the energy, just to see what would happen.
Their tremendous pace continued, but the pressure began to mount. The monster was diving. Or was it that? An inspiration; he switched on the energy again. The flaming in the green stuff commenced anew. Once more the pressure outside was decreasing. It was due to a gas generated in those digestive juices by the energy. They were making a veritable balloon of a living creature, their own container plugging its throat to retain the gas.
Burke could envision the bloating of the vast body which was taking place to such an extent that the weight of water displaced was considerably greater than its own. He found he could vary its buoyancy by manipulating the rheostat and thus regulate the speed of ascent. They were in the body of a living, though probably slowly dying, submarine balloon that was to an extent navigable. But the creature continued to propel itself madly in the northeasterly direction and this was entirely out of control. "What a belly-ache it must have!" thought Burke, grinning in spite of himself.
* * *
He was careful to keep the current low so they would not rise too swiftly, knowing that if the ascent became so rapid as to permit insufficient time for internal and external pressures to equalize, the creature would explode violently. Though he couldn't see how it would do him any good personally, he had a mad desire to get up to the surface. If the monster should expire then, as undoubtedly it would, and its carcass should float, there was still a bare chance for life. Even if it did mean prison for himself. He wondered how much pressure difference the thickly armored hide of the beast would stand. How much stretching due to the expansion in volume by tissue penetration of the gases. Undoubtedly there was some escape through natural orifices other than the gullet. Enough to act as a safety-valve, he hoped.
Augustine was stirring, groaning. The pressure gauge showed less than two thousand pounds when he tottered to his feet. Burke wasn't at all sure now how nearly this was an accurate indication of depth, since he didn't know the pressure differential between the inside and outside of their animate balloon. He thought this differential would not be very great. Their forward speed was slowing considerably; the monster was losing strength.
The professor gazed disbelievingly at the instruments. "Dick!" he exclaimed. "We're going up. We're saved!"
"Not yet," -- drily. "Think it out, stupid. We've a chance in a million, is all."
Fifteen hundred pounds, a thousand. The swirling green murk outside the ports had almost vanished. Burke could see the distended wall of the creature's stomach. It was dripping great blobs of sticky black stuff from several torn spots. The thing was hemorrhaging internally. He backed off further on the rheostat and the pressure gauge pointer moved slowly toward the lower end of the scale. They would have to keep their carrier intact as long as possible.
Augustine was talking again and was still excited. "You're wrong, Dick. There's more than a chance in a million; there's a good chance. Listen: I see you're easing it upward as gently as possible. That's right. We'll make the surface. The monster will die, of course; it's dying now. But it will float when we get up there. The carcass won't burst. Not if the pressures inside and outside are kept from differing too greatly, especially too suddenly. Don't you see?"
"Sure I see. As far as you've gone. So then what?"
"Why, the televis, naturally. We can start calling for help even before we're afloat -- a thousand feet before. Our own ship, any ship can easily come to us. We're saved, I tell you!" The professor's voice screeched as he tried to convince himself of his own words.
"Ever stop to think how much battery power this is taking? Take a slant at the charge indicator."
Augustine gasped. The battery charge was already down to thirty percent of full capacity. "I -- I didn't think of that," he faltered.
"Lots of things you haven't thought of," sneered Burke. "For one, the murder rap that'll be facing you if you do get up top alive."
This was a blunder. Burke had underestimated his companion's cunning and the courage which would come from desperation. In fact, he'd talked too much. He'd put ideas into the other's head that wouldn't have sunk in of their own accord.
The professor's voice changed subtly. He moved near and peered at the pressure gauge. "Eight hundred fifty pounds, two thousand feet," he murmured. Then: "You wouldn't turn me in, would you, Dick?"
"What did you do to me?"
Then, taken completely by surprise, Burke went down under the full weight of the enraged scientist. As he lurched from the instrument table, his hand automatically clung to the rheostat handle. He felt it slam over to the full "on" position. Then his grip tore loose.
* * *
Augustine's pudgy but powerful fingers twisted around his windpipe as they rolled over and over on the floor. Burke tore at them frantically, finally got them free. The squid mustn't explode!
"You fool!" he croaked. "The energy's full on. We'll go up like a shot. We'll --"
The professor, fighting blindly, evidently did not get the import of the scarcely intelligible words. He was pounding at Burke's face with everything he had and it was all the younger man could do to wriggle himself free and roll back against the wall.
"The energy!" he managed to howl before Augustine's two feet struck him together. "You damn --"
He lashed out blindly as pain from the heavy double kick flashed racing torture through his body. With sudden new energy, he scrambled erect and dived for the rheostat. Then he came down hard with his chin on the table. His antagonist had wrapped those huge arms around his knees and was dragging him down. Hell of a way to fight! Thoughts weren't at all clear now to Burke but he knew he must get to that rheostat. They were rising like a rocket.
"Wait, Prof!" he groaned.
He twisted free and lurched upward, starting a swift right to his opponent's bobbing jaw. But it never landed. There came a terrific wrench and a simultaneous crash as of the entire universe disrupting. Then utter blankness.