The detective twirled his moustache, and his eyes sparkled. “Ah, but do we know that? Yes, M. Lestrange was stabbed repeatedly in the chest, and yes, the only knife on this airship belongs to the cook, and yes, he was found later on clutching this same knife, giggling and writing ‘Lestrange’ in the man’s own blood. But can we prove that he was the killer?”

The expressions of the passengers, gathered in the first class lounge, ranged from shock to incredulity. Finally, Hugo Michkin, the American shipping magnate, spoke up.

“Ridiculous! If the cook didn’t do it, who could have done? And are you forgetting the incident with the razor-edged quiche?”

The detective merely smiled in a knowing manner, and strode towards the back of the room, where an easel stood with a cloth over it. Whipping back the cloth, the detective revealed a large blackboard, with lines connecting photographs of the passengers, blueprints, and other pieces of evidence.

“Now, mes amis,” said the detective, “I shall explain all.”