Since Harekaze reached the equator, engineer Maron Yanagiwara decides to organize an Equator Festival on the Harekaze. Meanwhile, the Blue Mermaids prepare an operation to distribute the antibody to the other infected ships, requesting help from the other students. As the day approaches, Maron becomes upset when she finds that no one seems to be excited for the festival. She soon cheers up when Hime Wazumi builds a palanquin for the event, and the other girls soon start getting into it. The festivities soon get underway with various performances and attractions, including a play, a sumo tournament, and finally a sing-along.