“ Mon ami ,” he replied, “you miss the point. I am looking for something that I do not see.”

“What is that?”

“A mistake⁠—even a little mistake⁠—on the part of the murderer.”

He stepped swiftly to the small adjoining kitchen, looked in, and shook his head.

“Monsieur,” he said to the manager, “explain to me, I pray, your system of serving meals here.”

The manager stepped to a small hatch in the wall.