The celebrated detective Monsieur Anton La Cranque has arrived to investigate an indeterminate number of murders that have happened on our train. He has recruited me as his sidekick - presumably because I have an honest face and a nice anorak - and together we are interrogating a woman who may or may not have been murdered. She had been helped into a seat and was looking pale and distressed.
"Now then Colin," said the celebrated detective. "Please to tell us why you have been murdered?"
"My name's not Colin," said the woman. "It's Trixie Glassenmeyer."
Monsieur La Cranque shrugged. "An obvious non-de-plume," he said to me over his shoulder. "It is no matter."
"And I have not been murdered," said Trixie, or possibly Colin. "I've just had a terrible shock."
"Being murdered would indeed come as a terrible shock, no?" La Cranque suggested.
"I suppose it would," said Trixie. "But I am absolutely certain that I have not been murdered. I would have noticed."
"Not, madame, if the murderer had crept up on you from behind," said La Cranque. "You could easily have been murdered without your knowledge. You could have simply carried on with your day without a care in the world until someone - let's say, for example, a suave and elegant Belgian detective - had pointed it out to you."
"I have not been murdered!" she insisted. "I merely fainted when I discovered that my chauffeur had been murdered."
"Ah ha!" cried Monsieur La Cranque. "So, it is your chauffeur who has been murdered? Finally, we get to the truth."
"Are you sure he has not merely fainted?"