At the center of the story is the Arianna, a sailboat with twelve passengers that sets sail for an ocean crossing. After a few days of navigation, due to a violent storm, the boat disappears from the radar. A year later, the wreck was found with only seven people on board, still alive. What happened to the others? What secret do the survivors hide? Each episode follows the complex events linked to the return of the castaways, alternating with the terrible period spent adrift to discover, step by step, the secret of their journey.