The detectives paused just inside the door and listened intently. The doors on the first floor were all closed and the rooms behind them appeared to be untenanted. At any rate, all was still on that floor. Subdued noises of various sorts floated down to them from above, however, seemingly from the third floor. They looked at each other significantly. Evidently, their theory had been correct--to some extent, at least. They approached each of the doors in turn, but could hear nothing. Under the stairway they found the expected door leading down to the basement, but, as it was locked, and there was no key, they paid no further attention to it. Instead, they started to mount the front stairs to the second floor. The stairway was old and rather creaky, but the detectives knew how to step in order to make the least noise. Consequently, they gained the next landing without being discovered. Here they repeated the tactics they had used below, with a like result. The sound of voices and footfalls were louder now, but they all came from the third floor. The second seemed to be as quiet as the first. The doors on the second floor, like those on the first, were all closed, but Nick ascertained that at least one of them was unlocked. That fact might be of great advantage in preventing discovery, in case any one should start down unexpectedly from the third floor, for the halls and stairs offered no place of concealment. The detectives noiselessly removed their shoes before attempting the last flight, and placed them inside the unlocked room, which they noiselessly closed again. They were now ready for the final reconnaissance. By placing the balls of their stockinged feet on the edges of the steps, they succeeded in mounting to the third floor without making any more noise than that produced by the contact of their clothing. A slight pause at the top served to satisfy them that the noises all proceeded from one room at the front of the house. They were already close to the door of this room, and they listened breathlessly. Words were plainly audible now, punctuated at frequent intervals by loud bursts of laughter. It sounded like a merrymaking of some kind. What was going on behind that closed door? Had they made a mistake in entering the house and wasted precious time in following a will-o’-the-wisp, when Helga Lund might be even then in the greatest danger? Nick and his assistants feared so, and their hearts sank heavily. But no. The next words they heard reassured, but, at the same time, startled them. The voice was unmistakably Grantley’s.