The room he had entered seemed ordinary enough--plain furniture, a davenport, chairs, a table. But the light! He stared about him. The room was filled with mellow light, yet there was not a single lamp to be seen. "Comes from everywhere and nowhere, that light," he whispered to himself. "Let me take your hat." The girl held out her hand. She seemed a nice sort of girl, rather boyish. When she walked it was with a long stride, as if she were wearing knickers on a hike. "I--I'll call Father." She marched across the floor. Johnny started from his chair, then settled back. Had he caught the gleam of an eye blinking from the wall? He thought so. But now it had vanished. The girl was still three paces from the door at the back of the room when, with a silence that was startling, that door swung open. Johnny looked closely. The hall beyond was lighted. There was no one to be seen. As if this was quite the usual thing, the girl marched straight through the open door. At once it closed behind her. Johnny was alone. If you have followed his career in our other books you will know that Johnny is no coward. He had been in tight places more than once. Persons much older than he had said he bore up under strain remarkably well. For all that, this place gave him the creeps. That it was not in the best part of the city he knew well enough. This brownstone house, as we have already said, was just across from the deserted Century of Progress grounds, and faced the lake. Back of it were shabby tenements and dingy shops where second-hand goods were sold and where auctioneers hung out their red flags. "Rather senseless, the whole business," he mumbled to himself. "Fellow gets into all sorts of strange messes trying to fight other people's battles for them. And yet--" His thoughts broke off. A small red light like an evil eye flashed above the outer door, then blinked out. A faint buzzing sound came from a clock-like affair on the wall. Then all was silent as before. "The professor's house," he muttered. "Queer place! Why did I come? Couldn't help it really. It was the boxes--the three black boxes." Ah yes, those three black boxes! First they had intrigued him, then they had aroused his interest and sympathy. After that there was just nothing to it. He had invested all but his last dollar in those three black boxes. Now he was trying to get his money back and do someone else a good turn as well. "But it seems," he whispered to himself, "there are dragons in the way, gleaming eyes, skeletons. All--" The red light flashed again, three times. The clock buzzed louder. "Wish she'd come." He rose to pace slowly back and forth across this room of many mysteries.