On the day of the Tennomifune Academy entrance ceremony, in the class 1-7 classroom, Hanakoizumi Anne (Hanako), Hibarigaoka Ruri (Hibar), and Kumegawa Botan (Botan) are told by their homeroom teacher Kodaira-sensei that they are unfortunate and unhappy students. The goal of the students of class 1-7, who are burdened by a variety of forms of misfortune, is to become happy. The three girls have trouble accepting their circumstances, but they're immediately given an unexpected assignment...!

It's been a week since the entrance ceremony. In class 1-7, the students' misfortune shines through in interviews and physical exams, causing quite the uproar. After school, Hanako, Hibari, and Botan go on a tour of the school's clubs with academy guide robot Timothy to find one right for themselves...

Today's lesson for class 1-7 of Tennomifune Academy is a dice game?! Hanako, Hbari, and Botan form a team and set out for the finish line, but at this rate they'll finish last. Meanwhile, their competitive classmate Hagyu Hibiki is determined to win as she drags along her childhood friend Ekoda Ren with her.

After losing the dice game that was part of happiness training, the girls are assigned to take pictures of their "lucky items" as homework. Hanako, Hibari, and Botan try to get together over the weekend to finish their assignment, but from the moment they meet, they experience misfortune after misfortune. For some reason Hibiki seems strangely competitive, and a sleepy-looking Ren begins following them as well... Will the girls be able to complete their homework?!

Hibiki gets lost when she's forced to walk to school alone. While angrily thinking about how Ren refuses to accompany her, she begins reminiscing about how they first met and became friends...

The subject of today's happiness training is "Good Luck Orienteering!" Lead by the assistant Timothy, Hanako and her friends arrive at a mountain near school. While experiencing typical levels of misfortune, the girls have a picnic, and Hibari realizes the true meaning of the happiness training.

Hanako gets a fever and leaves class early. Hibari and Botan go to visit her at home with gifts and the day's homework. When Hanako misses school the next day, the four girls of class 7 begin creating something that makes wishes come true...

After finishing their final exams in the basic subjects, the girls are only allowed a moment's relief before being told they're taking a "special happiness test!" Even farther underground the gym's basement facility they once visited, the girls are subjected to a virtual exam!

Class 7 has its first joint lesson with another class. Washinomiya-sensei, the other class' homeroom teacher teaching the cooking lesson, accuses Hibari and her friends of lacking awareness. Refusing to allow her comment to discourage them, the girls continue with the class, but...

Summer vacation has finally begun. Botan records the fun days she is having with her friends from class 7 in her journal. Going to karaoke on the way home from school, swimming at the beach by the Kumegawa villa... As they describe their summers filled with "happiness," she smiles.