"And yet it is simple," Tchigorsky replied. "Here is a form of electric battery in the vault connected by tiny wires to every sleeping chamber occupied by a Ravenspur. In each of these bed-rooms a powder is deposited somewhere and the wire leads to it. At a certain time, when you are all asleep, the current is switched on, the powder destroyed without leaving the slightest trace, and in the morning you are all as dead as if you had been placed in a lethal chamber--as a matter of fact, they would have been lethal chambers. "Almost directly, by means of the chimneys, etc., the rooms would begin to draw a fresh supply of air, and by the time you were discovered everything would be normal again. Then the battery would be removed and the wires withdrawn without even the trouble of entering the rooms to fetch them. Then exit the whole family of Ravenspur, leaving behind a greater mystery than ever. Now do you understand what it all means?" Geoffrey nodded and shuddered. "What do you propose to do?" he asked. "Leave the battery where it is, and----" "Unless I am mistaken, the battery is removed already," said the Russian. He was correct. Investigation proved that the whole thing had been spirited away. "As I expected," Tchigorsky muttered. "Done from the vaults under the sea, doubtless. That woman's servants keep very close to her. It is wonderful how they manage to slip about without being seen. They have ascertained that an accident has happened to their mistress, and they have removed signs of the conspiracy. But for the present they cannot remove their mistress." Tchigorsky chuckled as he spoke. "You seem pleased over that," said Geoffrey. "Of course I am, my boy. It enables one to do a little burglary without the chance of being found out. And you are to assist me. But I am not going to start on my errand before midnight; so till then I shall stay here and smoke. At that hour you will please join me." "I am to accompany you, then?" "Yes, you are going to be my confederate in crime." Geoffrey joined the others downstairs. Delight and thankfulness were written on every face. Never had Geoffrey found his family so tender and loving. Usually, Marion had had her feelings under control, but to-night it seemed as if she could not make enough of her cousin. She hung over him, she lingered near him, until Vera laughingly proclaimed that jealousy was rendering her desperate. "I cannot help it," Marion said half tearfully. "I am so glad. And if you only knew--but that does not matter. I am beside myself with joy." "I suppose that woman upstairs is all right," Ravenspur said coldly. He was by no means pleased that Mrs. May should have intruded twice in that way. And each time there had been some accident. With so much sorrow weighing him down and with the shadow of further disaster ever haunting him, Ravenspur was naturally suspicious.