"Four of me hearties was swept overboard an' drowned by that bomb." Ben O'Gard roared. "The swabs are in Davy Jones's locker."

The thugs split like butter before a hot knife as Doc went through them. A vault, and he was out on deck. He had his valve along.

Ben O'Gard's men were frantically assembling the folding seaplane.

Doc scanned the skies.

"Where's the plane?" he demanded.

"Figure it went back after another load of bombs," boomed Ben O'Gard. "Rust my anchor, matey. We gotta shake a mean leg, or it'll be back 'fore you set sail in the air."

The Helldiver was indeed aground. The bow canted half out of the water. The stern portion of the deck slanted down beneath the surface.

Around about was a glacier-walled cove. Ordinarily, it would have been a snug-enough harbor. But the attack from the air had turned it into a trap.

Doc scrutinized the heavens once more. His strange golden eyes sought everywhere for the shabby plane flown by his friends. There was no sign of it.

Doc juggled the all-important valve. Some of Ben O'Gard's men eyed it enviously. Doc had no idea of surrendering it, though.

"What became of my friends?" he questioned.

Ben O'Gard shrugged his walrus shoulders.

"The last of 'em I saw, they was fightin' Keelhaul de Rosa's sky tub." He leveled an arm which was a cone of beef. "The fracas wandered off down that way."

He was pointing down the glacial coast of the uncharted land.

No line changed on Doc Savage's firm bronze features. But inside, his feelings were far from pleasant. The shabby old seaplane flown by his friends was no fighting craft. An Immelman or a tight loop would pull her wings off.

The tiny folding seaplane was now ready for the air.

"Take 'er off, matey," howled Ben O'Gard. "Rust my — " He fell silent. The drone of a plane had come to their ears. "That's Keelhaul de Rosa comin' back," bawled the walrus. "Hurry, matey. Our lives is in your hands."

"I wish they were," Doc said under his breath. Then, aloud:

"Give me the best machine gun. And throw every other weapon overboard."

"Aw, don't worry about us keepin' our hands offn you from now on,' fawned the walrus. "Why, we'll cut you in on a share of the boodle — "

"Over with the guns," Doc rapped.

There was more squawking. But the motor sound of the approaching plane was like the howl of doom. No argument could have been more persuasive. Falling pistols, rifles, knives, and machine guns whipped the surrounding water into a foam.

Doc waited until the last arm vanished.

Then his mighty bronze form plugged into the tiny seaplane cockpit. The motor purred like a big cat.

He took the air. The all-important valve went with him.

HE WAS none too soon. With a bawl like a banshee spawned by the foul gray haze overhead, Keelhaul de Rosa's plane dived. It opened with a machine gun. The craft had come into the arctic spurred for war. It had a pair of cowl guns, synchronized through the prop.

Every fourth or fifth slug it fired was a phosphorus-burning tracer. The bullets scuffed the water below Doc's fleet little flivver craft. In the green sea, before they were extinguished, the tracers glowed like a streak of scattered sparks.

Cobwebby, gruesome, tracer strings waved before Doc's golden eyes. Phosphorus fumes reeked in his nostrils. Lead gashed a hole in the right-wing bank. The flivver wouldn't stand much of that.

Doc banked quickly. The tiny seaplane was agile as a fly in his master hand.

Twice more, Keelhaul de Rosa's killer craft dived angrily. Its lead missed both times.

Ben O'Gard and his gang now gathered the fruit of all that squawking about giving up their guns, They had delayed Doc almost too long.

Keelhaul de Rosa's plane swooped upon the Helldiver. It released an elongated metal egg. This hatched a choice lump of hell alongside the submarine. Water geysered two hundred feet in the air. A huge wave sprang outward in a circle.

Over heeled the sub, over — over. It writhed. It skewered like a tadpole out of water.

Then it slipped free of the ledge upon which it had been hung.

For a long minute, the Helldiver was lost under the water. Then it came up — and floated.

Doc flung his flivver for the other plane. If size of the craft had been important, the scrap would have been ridiculous. Doc's steed was to the other like a sparrow to a hawk. But size counts little in an air battle.

Doc, however, was handicapped by having to fly his plane and shoot his sub-machine gun by hand at the same time.

He jockeyed in above the enemy. His rapid-firer burred noisily, the breech mechanism spewing a string of smoking empty cartridges.

The other plane jumped in the sky like a thing bitten,

NO SERIOUS damage had been inflicted, however. The two craft sparred wanly. At this, they were about evenly matched.

Keelhaul de Rosa's seaplane was a low-wing, all-metal job of late production. Its two motors were huge and speed-cowled for efficiency. Even the pontoon floats were streamlined in a fashion which made them virtually another pair of small wings.

Only two men occupied the craft.

Neither of these was Keelhaul de Rosa. They had, rather, the wind-burned look of professional airmen of the northland. Probably Keelhaul de Rosa had picked them up to do his flying.

The jockeying for position ended suddenly. A quick flip of Doc's bronze wrist, a gentle pressure from one foot, and the tiny seaplane pounced like a bull pup. It was doubtful if the pair in the big plane understood quite how the maneuver had been managed. But Doc was upon them while the pilot still goggled through the empty sight rings of his cowl rapidfirers.

Doc's small machine gun shimmied and lipped flame. His bullets pushed cabin windows out of the other ship. They tore the goggles off the other pilot.

The big plane did half a wingover, eased into a dizzy slip, and would have collided with Doc's little bus. He evaded it by zooming sharply.

The second man in Keelhaul de Rosa's craft took over the controls.

Once again, the man-made birds skulked each other's sky trails warily. The motors panted and steamed. The evil gray mist squirmed and boiled in the prop wakes.

Doc got in a burst. His lead started colorless streams of liquid stringing from the wings of the other plane. He had opened the fuel tanks in the wings.

In return, he took a lead-whipping that gnawed a ragged area in the fuselage of his little fiivver. After that, the craft flew with a strangely broken-backed feel.

Then fresh trouble loomed. Doc's fuel gauge needle had retreated a lot. It already covered the first two letters of the word "empty." There had been no time to charge the fuel tanks before he took off.

Doc calculated. Fifteen minutes more, and he would have to come down. He'd better finish this sky brawl quickly.

For the second time. Doc's small craft pulled its bewildering pounce of a maneuver. His gun hammered. Lead went home to vital points of the opposing plane. The plane climbed up on its tail and hung hooting at the borealis. It slipped off on a wing tip. It rocked into a tailspin.

It hit a floe hard enough to knock a hole through four feet of pan ice. After that, nothing was left but a wad of tin and wire sticking out of the ice.

Doc slammed his bus back for the cove. He found it in the gray haze.

A disquieting sight met his gaze.

The Helldiver was stealing straight for the open sea — or, rather, the ice-covered sea. All hatches were battened.

Doc's powerful bronze hand closed over the tank valve. He had it in the plane cockpit. If the submarine dived with the tank open, it would never come up.