Every year, around 20 people mysteriously disappear from cruise ships at sea. No one has ever returned. Until now.

Martin Schwartz, a police psychologist, lost his wife and son five years ago. It happened during a vacation on the cruise ship "Sultan of the Seas" - no one could tell him what exactly happened. Since then, Martin has been a psychological wreck, numbing himself with dangerous undercover missions.

In the midst of an operation, he receives a call from a strange old lady who claims to be a thriller author: he must absolutely get on board the "Sultan," as there is evidence of what happened to his family. Martin had vowed never to set foot on a ship again - yet he follows the lead and discovers that a girl who went missing on the "Sultan" weeks ago has reappeared. Holding his son's teddy bear in her arms.