I enlightened him with a touch of malice. “One of our ample staff of private detectives happened to see you in a car on the Cranchester road yesterday,” I explained.

Poirot’s bewilderment vanished. He laughed heartily. “Ah, that! A simple visit to the dentist, c’est tout . My tooth, it aches. I go there. My tooth, it is at once better. I think to return quickly. The dentist, he says no. Better to have it out. I argue. He insists. He has his way! That particular tooth, it will never ache again.”

Caroline collapsed rather like a pricked balloon.

We fell to discussing Ralph Paton.

“A weak nature,” I insisted. “But not a vicious one.”

“Ah!” said Poirot. “But weakness, where does it end?”

“Exactly,” said Caroline. “Take James here⁠—weak as water, if I weren’t about to look after him.”