Flame lighted the interior of the control room and their eardrums were almost shattered by the deafening roar of a gun discharged at close range. The man Tim had tackled was shooting at the sound of their voices. "Never mind trying to get this fellow," called Pat, now safely protected by the bulkhead into the engine room. "We'll pick him off when he tries to return to the deck." The answer to Pat's words were written in smoke and flame as the unknown intruder fired again. Tim, watching the outline of the hatch against the sky, saw a head appear. He raised his gun and fired in the general direction of the hatch, more to scare the second man than to actually harm him. On the echo of the crash of his gun came a scream of pain and the head promptly disappeared. "Good shooting!" cried Pat. "Now we'll get this fellow. He's in a cross fire. Next time he shoots let him have it. I'll see if I can get around to the switch and turn on the lights. This party is going to end all of a sudden." Tim strained his senses to detect the spot where the gunman was hidden. He could hear cautious sounds but he didn't dare fire for fear of hitting Pat. Tim edged near the ladder which led up to the hatch. As he neared it he became conscious of some one crawling up the ladder and he lunged toward the shadowy form. Just as Tim moved, the man on the ladder lashed out viciously with one foot. The blow caught Tim squarely on the chin and he dropped to the deck, out cold. His gun clattered from his nerveless hands and the man on the ladder leaped for the hatch just as the interior of the _S-18_ blazed with light. Pat, momentarily blinded by the glare, recovered in time to see the legs of their assailant disappearing over the edge of the hatch and with snap aim he sent a volley of shots crashing upward. Feet pounded along the deck of the _S-18_ and Pat heard the sudden splashing of oars as a small boat pulled away from the hull of the sub in great haste. Pursuit, he knew, was useless and he bent over Tim. The flying reporter was recovering his senses, but he was still groggy from the sharp blow on his chin. His first thought was one of self defense and he struggled weakly to raise his fists and hammer at Pat. "Snap out of it," said Pat, shaking Tim gently. "The show's all over and we're still in command of the fort." Tim smiled a little sheepishly. "Someone certainly landed a haymaker on me." "You mean a No. 11 shoe connected with your chin at about sixty miles an hour," chuckled Pat. "A kick like that would have killed anyone but an Irishman." Tim shook himself to make sure that he was still all together and got to his feet. He was still a little shaky. "You stay down here while I go on deck and see what it was all about," said Pat. He climbed nimbly up the ladder and disappeared just as cries sounded along the dock. "On board the submarine," boomed a heavy voice. "What's the matter down there?"