Hiroshi is a seemingly ordinary young man that works part-time at a gyoza shop, but the reality is he’s actually a fortress for a planet! Each of his movements is produced by someone inside him steering, which is why he goes through life without getting entangled with other humans. Due to an incident, Shizuka begins to have feelings for Hiroshi, and Akemi suddenly becomes captain of the fortress and must handle these new complications while trying to find a new future for her planet.