We arrived at Darnétal three minutes after the departure of the train. True, I had the consolation of learning that a man wearing a gray overcoat with a black velvet collar had taken the train at the station. He had bought a second-class ticket for Amiens. Certainly, my debut as detective was a promising one.

Delivet said to me:

“The train is express, and the next stop is Montérolier-Buchy in nineteen minutes. If we do not reach there before Arsène Lupin, he can proceed to Amiens, or change for the train going to Clères, and, from that point, reach Dieppe or Paris.”

“How far to Montérolier?”

“Twenty-three kilometres.”

“Twenty-three kilometres in nineteen minutes.⁠ ⁠… We will be there ahead of him.”