You board a ship with nine other cadets, but the manifest says eleven. One of you doesn't belong, and the other nine are all looking at each other like threats. It's a locked-room mystery that trusts you to solve it alongside the cast, counting heads and catching lies, paranoia clicking into place each time someone moves wrong. Ninety minutes is all it needs. The premise does the heavy lifting, and this film never wastes a second proving why it should have aged into legend instead of obscurity.

Ten applicants to the Cosmo Academy, an elite school founded under the Interstellar Alliance whose graduates are promised top positions, reach the last stage of its entrance exams. Among them is Tada, a Terran. Their group is sent to the Esperanza, a derelict ship drifting in orbit, where they must hold out for 53 days with no contact with the outside apart from an emergency button that means giving up. Then they count heads and find eleven people aboard. One of them is an impostor, and nobody knows who or why. As the candidates watch one another for any slip, suspicion spreads through the group in this science fiction mystery film that mixes adventure, drama and romance.