"And Derek?" said Lenox.
"Who knows?" said Poirot, with a shrug of his shoulders. "But I will tell you this, Mademoiselle. I am not satisfied; no, I, Hercule Poirot, am not yet satisfied. It may be that this very night I shall learn something more. At least, I go to try."
"You are meeting some one?"
"Yes."
"Some one who knows something?"
"Some one who might know something. In these matters one must leave no stone unturned. Au revoir, Mademoiselle."
Lenox accompanied him to the door.
"Have I—helped?" she asked.
Poirot's face softened as he looked up at her standing on the doorstep above him.
"Yes, Mademoiselle, you have helped. If things are very dark, always remember that."