Running out on to the lawn, Puttler searched beneath the window. Yes, there were the marks of the ladder in the mould of a garden bed, and on the ladder itself he found confirmatory proof. Lifting it against the wall, he scrambled up, and came breast-high to the window sill on its topmost rung. Drawing himself up, he sprang into the room and looked round for some clue. By this time Mary Wenner, followed by Dick, had come through the door.

“Her dressing-gown isn’t gone!” whimpered Mary, pointing to the hook where it hung. “But her shoes are. She must have dressed, and I didn’t hear.”

The tired man at the door had heard no sound in the night. A thick carpet covered the floor. Mary said that, when she woke, the door which communicated between the two rooms was closed.

She had heard no sound at all, and claimed that she was a light sleeper, which, in fact, she was not. When she had gone to sleep the candle was burning. Examining this, Dick saw that it could not have been alight for more than an hour. There were two burnt matches in the tray, which meant that the candle had been extinguished once and relit again.

“I wonder she didn’t wake me; I’m usually a light sleeper.”

Dick left the girl explaining to the watcher who had been on guard outside the door.

“It was her voice, of course, that the patrol man heard in the dark. I blame myself that I didn’t jump at that idea.”

“I’d like to keep all the blame!” said Dick bitterly. “Oh, God! it doesn’t bear thinking about!”

He went away on a solitary search; none saw him slip through the back of the house, and he moved under cover of the river bank. When he returned, after an absence of two hours, Puttler told him that there was a message from the Home Office awaiting him. That institution had rung up twice. Dick got through after a wait, and learned that he was talking to an important under-secretary.

“Could you run up to London for an hour?”

“Is it necessary?” asked Dick, and he explained with all rapidity the happenings of the night.

“I’m afraid you had better see us as soon as you possibly can. In view of all the circumstances you cannot come too soon.”

With a curse Dick hung up the receiver, and this time he took Harry’s big two-seater, a car that his brother had only used a dozen times, but the use of which he had steadfastly refused to anybody else.