Mr. Zimit, a philosophy teacher at an international school in Jakarta, has been challenging his class of twenty with thought exercises to prepare them for their future. On the last day of school, he holds an exercise in which he posits an oncoming atomic apocalypse. There is a bunker to shelter them for a year, but it only has supplies for ten people, so his students have to decide who of them should be allowed in. The top student, Petra, initially refuses to participate, but Zimit threatens to lower her boyfriend James' academic score if she does not.