* * * *

Captain Robert Knapp's sense of things was badly disordered. He had
just heard a story which his common sense told him couldn't be true,
but which the evidence of his eyes had grimly authenticated. He had
seen fifteen men slung aboard his ship from the _NX-1's_ silent hull;
men stretched in grotesque, limp attitudes; men struck down by a
paralyzing ray. Why, no nation on earth had developed rays for
warfare! Yet--a crew of helpless men was even then in the sick bay,
receiving attention in the hope that they might recover.

"You're going right through that cavern, then, Wells?" he asked
incredulously. "You're going to investigate what lies beyond?"

"Nothing else! And I won't come out till I've blown that octopi ship
to pieces!"

"It sounds preposterous," Knapp murmured, shaking his head. "Octopi,
you say--and clad in metal suits! Running a submarine more powerful
than the _NX-1_! Armed with a ray--a paralyzing ray! I can't
believe--I can't conceive--"

"You've seen the men!... Knapp, if I were you I'd swing my
eight-inchers out, bring up the plane catapult and keep the deck
torpedo tubes loaded and ready. It's best to be prepared; God knows
what's going on underseas these days!"

First Officer Graham appeared at the door. "Work finished, sir," he
said. "Ready to cast off."

"Thank heaven!" Wells muttered, and stretched out his hand to Robert
Knapp. "Broadcast what I've told you, Bob, and say that the _NX-1_
won't be back till everything's under control. I'll keep in touch with
you. So long!" And he was gone before the captain could even wish him
good luck.

* * * * *

Orders raced from her commander's fingers on the stud board in the
control room. "Crash Dive" filled her tanks and put her nose
perilously down, so that in thirty seconds only a swirling patch of
water was left to show where once she'd lain. A brief command to the
helmsman and she pointed straight for the dark cavern marked on the
chart.

When well under way, Keith descended with Graham to inspect the new
torpedo firing system, and found it in good working order. "Graham,"
he ordered tersely, "instruct the crew fully about rushing to the
control room on one ring of the general alarm. And send the cook up to
me in a minute or so. I'll be in Sparks' cubby."

Above again, he instructed the radio man to rig a remote control
sender and receiver in the insulated control room. The need for