It sank to the level of Lupin's smoking-room and stopped.

The doors flew open, Dieusy and Guerchard sprang out of it; and on the instant the brown-faced, nervous policeman sprang actively on Guerchard and pinned him.

Taken by surprise, Guerchard yelled loudly, "You stupid idiot!" somehow entangled his legs in those of his captor, and they rolled on the floor.

Dieusy surveyed them for a moment with blank astonishment.

Then, with swift intelligence, grasped the fact that the policeman was Lupin in disguise.