Outside the island, there is emptiness: the world has been destroyed by a fog that has engulfed the planet and is killing everyone it touches. On the island, there is an idyll. One hundred and twenty-two inhabitants and three scientists live in peace and harmony. Suddenly, one of the scientists is found brutally murdered. And then it becomes clear that this murder has set in motion a process of weakening the island's defences - the only barrier that holds back the pernicious fog. If the crime is not solved in 107 hours, the fog will swallow the island and all its inhabitants. But there's another problem: the security system has erased everything that happened the day before from the residents' memories. This means that the killer is still among them - and he doesn't even know it. And the clock is ticking...