As passengers board the overnight ferry from the Netherlands to England, a desperate little man frantically pleads for a cabin as if his life depends on it. But the fery is overbooked, and his only choice is to sleep in a lounge with everyone else, including Chief Superintendant of Scotland Yard Henry Tibbitt and his wife Emmy, who are returning from an Amsterdam holiday. The next morning, the man is found dead --- murdered by someone who had to have been in the lounge that night ---- and Inspector Tibbett finds himself obliged to investigate ...