The victim must instantly fall down as though dead, and Mr. Bathgate must give one good smack at that Assyrian gong there behind the cocktail tray and make off to whatever spot he considers least incriminating. As soon as the lights go off and we hear the gong, we must all remain where we are for two minutes… you can count your pulse beats for a guide. At the end of two minutes we may turn up the lights. Having found the ‘corpse’ we shall hold the trial, with the right, each of us, to cross-examine every witness. If Mr. Bathgate has been clever enough he will escape detection. I hope I have made everything reasonably understandable.”

“Pellucidly explicit,” said Doctor Tokareff. “I shall enjoy immensely to take place in sush intellectual diversion.”

“He isn’t a bit pompous really,” whispered Angela in Nigel’s ear, “but he memorizes four pages of Webster’s Dictionary every morning after a light breakfast. Do you hope Vassily chooses you for ‘murderer’?” she added aloud.

“Lord, no!” laughed Nigel. “For one thing I don’t know the lie of the land. Couldn’t you show me round the house in case I have to?”

“I will… to-morrow.”

“Promise?”

“Cross my heart.”

Rosamund Grant had wandered across to the foot of the stairs. She drew a long subtly-curving dagger from the strip of leather and laid it flat upon her palm.

“The murderer has plenty of weapons to hand,” she said lightly.

“Put the beastly thing away, Rosamund,” said Marjorie Wilde, with a note of very real terror in her voice; “they give me the horrors… all knives do. I can’t even endure watching people carve… ugh!”

Rankin laughed possessively.

“I’m going to terrify you, Marjorie,” he said. “I’m actually carrying a dagger in my overcoat pocket at this very moment.”

“Are you, Charles? But why?”

It was the first time Nigel had heard Rosamund Grant speak to his cousin that evening. She stood there on the bottom step of the stairs looking like some modern priestess of an ancient cult