Aurélie, an inspector who clumsily let a young man suspected of being involved in the disappearance of his girlfriend go, learns that he was arrested on a Swiss merchant navy cargo ship for the murder of a sailor. Sent to South Africa to repatriate him, she discovers that the missing girl was a passenger on this cargo ship a few weeks earlier. She continues her investigation alone, facing resistance from the crew.
Aurélie Mercier, a former inspector transferred to the municipal police, must repatriate Florian, arrested for murder on a Swiss cargo ship. On board, she learns that the young man's girlfriend, who has been missing for weeks, was an incognito passenger. Aurélie senses that the truth is not what it seems and that this cargo ship is full of secrets.