"ACTION Stations!"

Billy Barcroft leapt from his bunk, labouring under the delusion that he had turned in only a few minutes before.

The deadlights screwed to the brass rims of the scuttles and the electric lights in the wardroom gave him the impression that it was still night, and it was not until he scrambled on deck that he was aware that grey dawn was breaking.

The wind had piped down considerably. The seas, still running high, no longer showed their teeth in the form of vicious, foam-crested breakers. Yet the decks of the "Audax" were at regular intervals ankle-deep in water, as the destroyer cut through the billows.

A cloud of steam, caused by showers of spray striking the hot, salt-encrusted funnel casings, drifted aft, temporarily obscuring the flight-sub's range of vision. As it cleared he could discern the greatcoated figures of Aubyn and his brother-officers on the bridge, and the indistinct forms of the men as they passed ammunition from the shell-hoists to the guns.

"Got her this time, sir," remarked a burly petty officer, the rotundity of whose figure was still further accentuated by the prodigious quantity of clothing he wore.

He pointed to a dark grey, indistinct object almost dead ahead, her outlines rendered almost invisible by the trailing clouds of smoke that poured from her funnels. Barcroft estimated her distance at two thousand yards. It was impossible to see whether she flew her ensign.

The vessel was a German ocean-going torpedo-boat, one of the nine which had stolen out of Zeebrugge. By sheer good luck she had gone northward over practically the extreme length of the North Sea without being sighted by the British patrols. An hour, or even half an hour earlier she might have slipped unobserved past the "Audax" without being seen by the latter. As it was, one of the British destroyer's look-out men "spotted" the strange craft in the deceptive half-light of the late autumnal dawn.

The "Audax" threw out her private signal by means of a flash lamp from the bridge. The stranger replied by an unintelligible jumble of long and short flashes.

"Either that is a Hun or her signalman is three sheets in the wind," declared Lieutenant-commander Aubyn. "Tell her to make her number, or we'll open fire. And wireless the 'Antipas'; give her our position, and say we are in touch with a suspicious craft."