As the others try to make sense of the attack the day before, Koharu encounters a new boy aboard the ship. With the threat of an insider, who can truly be trusted?

Kakeru deploys a creative tactic to force Nanami and Akito to get along. Meanwhile, Mikoto and Sakuya patrol at ground level to search for the man who attacked the ship.

With the journey ending soon, the crew decides to have fun with a dare contest. However, wounded hearts and hidden intentions threaten the safety of everyone on the ship.

Mikoto’s been kidnapped, and Sakuya, Masaume, and the others launch a search. With war on the horizon, they are forced to learn the truth about their world’s dark history.

With Koharu still missing, Kakeru returns to the surface to find her and his father. Meanwhile, Akito and Nanami prepare to reveal their secret to a member of the ship.

The group is finally reunited aboard the ship. The Reset weighs heavily on their minds, and Koharu fears the inevitable global consequences of their decision.