The prestigious Cosmo Academy draws applicants from every stellar nation across the galaxy. Among them is Tadatos Lane, a young orphan esper from Terra. The final phase of the academy's entrance exam involves a dangerous mission simulation conducted on a genuine derelict starship. Candidates travel to the ships in groups of ten, yet when Tada's team arrives at the Esperanza, they are shocked to find their group now consists of eleven members. As the test unfolds, complications arise and the mood becomes increasingly strained. The crew starts to suspect sabotage, with Tada emerging as the prime suspect.