Robinson glanced at his watch. He led Bobby and the detective to the library.
"Then try your scheme if you want," he said, "but understand I assume no responsibility. Honestly, I doubt if it amounts to anything. You'll shout out if you are attacked, or the moment you suspect any real cause for fear. Rawlins will be in the corridor, and I'll be in the library or wandering about the house—always within call. Rawlins will guard the broken door, but be sure and lock the other one."
The two officers went upstairs with Bobby. Graham followed.
"You understand," Robinson said. "I'd rather Paredes and the doctor didn't suspect what you are going to do. Change your mind before it's too late, if you want."
Bobby walked on without replying.
"You can't dissuade him," Graham said, "because of what will happen to-morrow unless the truth is discovered to-night."
In the upper hall they found Katherine waiting. Her endeavours were hard to face.
"You shan't go there for me, Bobby," she said.
"Isn't it clear I must go in my own service?" he said, trying to smile.
He wouldn't speak to her again. He wouldn't look at her. Her anxiety and the affection in her eyes weakened him, and he needed all his strength, for at the entrance of the dark, narrow corridor the fear met him.