"And what do I get," the man asked, "if I do discover the staying place of that gentleman?"

"A ten-pound note," I answered, "down on the nail."

A slow smile suffused Fritz's face.

"I will tell you now," he said. "You have the ten pounds, so?"

"I have it ready," I answered, rising to my feet. "Come on, Fritz, you are a brave fellow, and I promise you it shall not end at ten pounds."

"You are serious?" Fritz persisted. "This is not a joke?"

"Not in the least," I assured him. "Why should you think so?"

The smile on the man's face broadened.

"Because," he said, "that gentleman—he is staying here, in this very hotel."

For a moment I was silent. The thing seemed impossible!