It’s the day before Golden Week, and the students of Asahigaoka Branch School listen to the voice of their unmotivated teacher, Kazuho, as they take tests. Natsumi struggles the most with the tests, so the others help her study during the break. Then, during Golden Week, the students agree to do their holiday homework together, so Renge decides to do something about their lazy teacher before the others arrive…

One morning, Natsumi uses a toy fortune dispenser to read Komari’s fortune, and tells it her, “bad luck: beware of water.” Komari says she won’t be near any water that day anyway, but when they get to school, they’re told that they’ll be cleaning the school pool… The next day, the Koshigaya sisters are bored at home on a day off from school, so Natsumi reads Komari’s fortune again and draws yet another “bad luck”…