The Raimu Unit pulls into a tropical island for repairs after their last battle leaves the battleship Amanohara severely damaged. What should be a straightforward pit stop becomes something else entirely when they arrive just as the island's Gogyou festival is getting underway. The stop also serves as a reward for the girls' service in combat. Umakai Shintaro and his five female students finally get a chance to breathe and enjoy the island, where they hear a tale of lovers connected to the Gogyou Shrine. The peace is short-lived. Enemy forces keep pursuing them, pulling the group back into combat. Between fending off attacks, Shintaro finds himself dealing with five girls who each try to win his attention. What unfolds is a blend of mecha action, comedy and fan service, where the tropical festival setting makes an unusual backdrop for both battles and romantic mischief.