A wealthy film producer, grieving the hit-and-run death of his wife a year earlier, invites a group of six friends to his yacht in the Mediterranean. Among them are a screenwriter struggling to find work, a fading actress, her talent-agent husband, a film director, and a gossip columnist. The host devises an elaborate game where each guest receives a card containing a secret about another guest. As the yacht cruises along the picturesque French Riviera, they stop at various ports for nightly quests designed to unearth these secrets. The tension rises as old friendships are tested, and long-buried grudges resurface. The guests realize that each of their secrets ties into a web of deceit and betrayal regarding their careers and personal lives.

As the game progresses, it becomes clear that this isn't just entertainment. The race to uncover the secrets turns sinister, and the line between truth and deception blurs. Unexpected alliances form, while paranoia and fear take hold. Real motivations behind the game begin to surface, leading to startling revelations about the guests' pasts and connections with the producer's late wife. Each participant grapples with their involvement in the twisted scheme, discovering some truths about human nature and moral choices. Tensions reach a breaking point as the yacht drifts under the moonlight of the Mediterranean, bringing a dangerous twist to the person orchestrating events from behind the scenes.