Suddenly there was no smile on Monsieur Dupont's face. Without the smile it was a very much less pleasant face.
"Two years ago, in my own country," his voice acquired a new snap, "some one asked me a riddle."
"A riddle?" Tranter echoed, surprised at the change.
"A very strange riddle. Unfortunately, I cannot tell you what it was. I cannot tell any one what it was. I undertook to find the answer. From France the riddle took me far away to another country—and there, after a year's work, I found half the answer. The other half is in London. And I am in London to find it."
"This is interesting," said Tranter, smiling slightly at the huge Frenchman's intense seriousness.
"You, my friend, can help me."
"I am at your service," the other promised.
Monsieur Dupont half-emptied his glass, and the smile began to reappear on his face in gradual creases. In a moment the shadow had vanished. He laughed like a jolly giant.
"Ah, forgive me! I had almost committed the crime to be serious. It is a fault that is easy in your London."