tom was stunned by the news. "there's no chance of a mistake?"

"judge for yourself," admiral walter replied. he read the message:

have just sighted enemy craft dredging out metal object

tom repeated the information to his father. both swifts were silent for a moment, exchanging dejected looks. then mr. swift remarked evenly:

"the game's never lost till it's over, son."

"you're right, dad!" tom exclaimed. turning back to the telephone, he said, "admiral, i'm not quitting. we'll take off as soon as i can get back to the base!"

with a hasty good-by to his father, and farewells to his mother, sandy, and phyl by phone, tom dashed out of the building. he sped to arv hanson's workshop, and the new hydrolung suits were loaded onto a small pickup truck and taken to the airfield. while flying back to fearing island in a helijet, tom received a radio flash from his father.

"another message from bud. he says the object dug up by the brungarians was not the missile. it appeared to be the metal section of a ship's prow, from some hulk buried in the silt!"

tom was jubilant. "terrific news, dad! our luck may be turning!"

at the rocket base tom detailed crews for the three undersea craft which were to take off on the expedition. arv hanson would captain one seacopter, mel flagler the jetmarine, while zimby cox, chow, and four crewmen would accompany tom in the sea hound.

because of their sonar-blinding systems, tom realized there was a chance of the ships losing contact with one another—especially if their analyzer sonars developed trouble. he therefore plotted their course to the south atlantic carefully, and issued orders for the antidetection circuits to be switched off every half-hour for a position check.

"report to your ships," he now ordered.

as tom was about to leave base headquarters, harlan ames telephoned from shopton. "bad news, tom. dimitri mirov has broken jail!"

"good night!" tom stifled a groan of dismay. "how did it happen?"

ames said the brungarian had somehow fashioned a crude weapon and overpowered the turnkey. disguising himself in the guard's uniform, he had slipped out before his victim was discovered.

"he must have had outside help within close call," ames ended, "because he seems to have made a clean getaway. the state police have spread a dragnet, but it doesn't look hopeful."

"he'll probably duck out of the country pronto," tom surmised. "anyhow, this won't stop us, harlan."

by nightfall the little fleet of three undersea craft was speeding southward at periscope depth. tom alternated at the controls with zimby, two hours on and two hours off. sleep came in snatches, the crewmen flopping on their bunks as the chance offered. chow's tasty meals helped break the monotony.

it was the following day when they reached the missile search area. tom surfaced the sea hound and reversed blade pitch, then gunned the rotor turbines for an aerial reconnaissance flight, while the jetmarine and the other seacopter stood by in the water.

"brand my guppies, it's some ocean, eh, boss?" chow remarked in an awed voice.

"big enough, all right," tom agreed with a grin. "and plenty of water to search in."

"no sign of the navy," zimby said.

tom nodded. "they pulled out on schedule."

"what about them brungarian sidewinders?" put in chow.

"that's the question!" tom swooped down to rejoin the other two craft. "we'll keep an eye out for enemy blips while we do our prospecting."

rather than lose time trying to contact bud, tom decided to let him find the sea hound. accordingly, he switched off the antidetection system and ordered all ships to submerge. arv's seacopter and mel's jetmarine were to maintain close formation and stand guard while tom's craft did the actual searching.

now the missile hunt began. tom had plotted a concentric search pattern, focused on the probable position worked out by the task-force computers. after checking his fix on the automatic navigator, tom switched on the damonscope and steered the sea hound on a gradually circling course.

the damonscope was mounted in a blister on the hull, its camera lens pointing toward the ocean floor. the automatic developing film would record any trace of fluorescence, and a red light would signal this result to the pilot's cabin.

minutes went by as the sea hound nosed slowly along through the gray-green gloom, its sister craft flanking it a hundred yards on either side. they were moving only a fathom or so above the bottom.

"a blip at eleven o'clock!" the sonarman called out suddenly. tom's pulse quickened. "moving straight toward us," the sonarman added.

tom surrendered the controls to zimby long enough to dart over and study the sonarscope. "i've a hunch it's bud," he told the others.

his guess proved correct when the unmistakable outline of a jetmarine loomed into view. tom flicked on the search beam for a moment, and bud could be seen waving through the cabin window. then the yellow glare went off, and bud's jetmarine glided away to take up a scouting position ahead of the sea hound.

an hour went by, then another. suddenly a flash of light stabbed through the murk from dead ahead.

"it's a signal from bud!" zimby exclaimed.

tom nodded grimly. "he's spotted trouble—probably an enemy sub." silence settled over the cabin as tom reached out to switch on the antisonar circuits.

at that same instant a red light flashed on the control panel. "the damonscope!" tom cried out. "we may be over the jupiter prober!"

cutting off the steering jets, tom gave a brief flick on the reverse jets to halt the craft. then he turned over the controls to zimby and began stripping down to don a hydrolung suit.

"gallopin' guppies! what're you aimin' to do?" chow exploded.

"go out and look for that missile," tom said calmly. "it's what we came for."

"are you loco, boss? what about that sub bud just spotted? mebbe it's mirov's bunch!"

tom refused to be dissuaded. after swallowing a space-plant pill, he armed himself with an underwater flashlight.

"think it's safe to show that light, skipper?" a crewman asked uneasily.

"if the enemy spots it, i'm hoping they'll think it's coming from a school of lantern fish or sea anglers," tom explained. he picked up a three-pronged digging fork with his other hand and went out through the air lock.

tom glided back to the spot which the sea hound had just passed over and began digging into the silt. presently he felt the fork strike something hard.

"an obstruction!" tom thought excitedly.

he probed deeper. bit by bit, a smoothly contoured and still-shiny metal surface became visible. "i've found it!" tom's eyes flashed in triumph, his heart pounding.

there was no doubt he had uncovered the nose cone of the missile which had re-entered the earth's atmosphere tailfirst!

meanwhile, bud, keeping watch on the enemy submarine, had seen a shadowy figure glide from its air lock and head in tom's direction. bud donned a hydrolung and followed.

"what's that he's carrying?" bud wondered.

suddenly the answer came to him—a self-propelled underwater grenade! horrified, bud jetted forward, tackling the diver at full speed.

a split second too late! the grenade went streaking straight toward tom swift!