Introduction by Martin Edwards.

The lights go off aboard the luxury transatlantic cruise liner, Meganaut, as it makes its way from New York to Paris. In the darkness, a gunshot rings out. And when the light is restored, a man is found dead in the smoking room.

But the situation becomes more complicated when the passengers realise that the deceased had apparently ingested cyanide just seconds before being shot. There are four psychiatrists aboard and they convince the captain to let them take a stab at solving the crime. Will their knowledge of the human psyche be a help or a hindrance? Can they figure out the puzzle’s solution before the killer strikes again?