A slight sound attracted Fenton Hardy’s attention and he slowly turned his head. When his gaze rested on the figures of the two boys who were stealing across the floor toward him he almost uttered an exclamation of amazement but he managed to check the involuntary utterance, although his face lighted up with relief. Quickly, the Hardy boys reached his bedside. Frank drew out his pocketknife and, without a word, without even a whisper, began to hack at the ropes that bound his father. But the knife was dull and the ropes were heavy. Joe had lost his knife in the water soon after they had left Bayport, and although he searched about the room, he was unable to find one, so he set himself to the laborious business of trying to untie the knots. Every moment was precious. At any second, the boys knew, they might hear the footsteps of the approaching smugglers. They worked with frantic caution, working against time. Frank hacked at the ropes, but the dull blade seemed to make little progress. Joe fumbled at the obstinate knots until his fingernails were broken, but he could scarcely loosen the strands. Minutes passed—slowly and agonizingly. Fenton Hardy could give no assistance. He had to lie there in silence, not daring even to encourage the lads by a whisper. The silence was broken only by the heavy breathing of the two boys, by the scarcely audible sound of the knife against the ropes. At last the knife cut through one of the ropes and Fenton Hardy’s feet were free. Frank pulled the ropes away, but a loose end fell on the floor with a light sound. Slight as the noise was, it seemed to them almost deafening, in view of the necessity for silence. Desperately, Frank prepared to set to work to cut through the ropes that bound Fenton Hardy’s arms. And, even as he reached over with the knife, they heard a sound that sent a thrill of terror through them. It was a heavy footstep beyond the door through which the smugglers had recently disappeared! Some one was approaching the underground room. Frank strained at the knife, but the ropes were stubborn. The dull blade made little impression at first. But at last the rope began to give, and finally, as Fenton Hardy gave a mighty effort, it snapped, and the detective was free. But the footsteps on the stairs had drawn nearer and it was followed by others. The smugglers were returning. “Quick!” whispered Frank, as he flung the ropes aside. “I—I can’t—hurry!” gasped out Fenton Hardy. “I’ve been here too—too long.” He could hardly utter the words. His face showed his exhaustion. “But we’ve got to hurry, dad!” came excitedly from Frank. “See if you can’t make it.” “I’ll—I’ll do my—my best,” returned his father. “If those fellows come back let’s fight for it,” put in Joe desperately. “You bet we’ll fight,” answered Frank in a voice that meant a great deal.