The boys stared at one another, aghast. For a moment they were dumbfounded. Then Jerry muttered: “I’m getting out of here!” and with that, he started for the door. “Me too!” declared Biff Hooper, and Chet Morton followed him as he rushed for the doorway. “What’s the big idea?” asked Frank, standing his ground. “Let’s stay and find what this is all about.” Joe, seeing his brother remain where he was, made no move to follow the others, although it was plain that the weird shriek had unnerved him. “You can stay,” flung back Jerry. “I’m not. This place is haunted, and I don’t mean maybe!” The three boys hastened through the doorway out into the hall and lost no time in regaining the front yard. Frank and Joe Hardy listened to their retreating footsteps. Frank shrugged his shoulders. “I guess it gave them a pretty bad scare,” he said to his brother. “We may as well go with them.” “I guess so,” replied Joe, greatly relieved. They were alone in the gloomy and deserted old house, and as they stepped into the hallway Joe cast a cautious glance up the stairway. But there was nothing to be seen. The upper floor was veiled in shadow. The house was in silence that seemed even heavier than before. When the two Hardy boys got outside they found the others waiting for them in the shelter of some trees about a hundred yards from the house. The three were discussing the strange occurrence in excited tones, and when the Hardy boys came up to them Jerry said: “I don’t have to be convinced any further. The place is haunted, sure. No other way to explain it.” “There’s not much sense in running away from a sound,” remarked Frank lightly. “If we had seen something, it might be different. I don’t believe in ghosts and I’d like to get to the bottom of this. It’s foolish to run away. Let’s go back.” Chet Morton and Biff Hooper looked a trifle ashamed of themselves because of their precipitous flight from the house while the Hardy boys had remained. “I got the scare of my life,” Chet confessed. “Just the same, I’m game to go back if you want to.” “How about you, Biff?” Biff Hooper scratched his head reflectively. “I’m none too anxious to go back in there again,” he admitted. “Not that I’m scared, of course!” he added hastily. “But I don’t see where we’d learn anything, anyway.” “Well, Joe and I are going back. That’s settled,” declared Frank. “We want to get to the bottom of this mystery.” “Mysteries are your meat!” observed Biff. “Well, when you come to think of it, this is a good chance for a little detective work.” He alluded to the fact that the Hardy boys were amateur detectives of some renown in Bayport. They came by their gift naturally, for their father, Fenton Hardy, had been for years on the detective staff of the New York police. Of late years he had been living in Bayport conducting a private detective service of his own with great success. He was known from one end of the country to the other as an exceptionally brilliant investigator.