Jirou Yakuin, a third-year high school student, has a crush on Shiori Sakurazaka, a classmate and childhood friend. He therefore hopes to be matched with her for the "marriage practical," which is a tradition at their school in which boy-girl pairings are chosen at random to live as mock married couples while being observed and graded on how close they have become. The vivacious Akari Watanabe wants to be paired up with her crush, the well-liked and attractive Minami Tenjin. Jirou and Akari are shocked to learn that Shiori and Minami have also been placed together, much to their dismay! Jirou and Akari are determined to be with their crushes, so they work hard to score as many points as they can because the top 10 pairs get to switch partners—as long as both couples are okay with it.