Hiratsuka-sensei asks the volunteer club to help her contribute to a local magazine themed around marriage. Since none of them, including Hiratsuka-sensei, knows anything about the subject, they ask someone who has experience "taking care of useless deadweight", namely Hatchiman's sister Komachi.

Iroha Isshiki takes Hachiman on a date to aid her in coming up with date ideas for her and Hayato.

The story begins when Komachi enrolls in Soubu High School and becomes the captain of the Service Club.