Kotoko, from the lowly F-Class, has a crush on Irie, who is the top-ranked student from A-Class. When she finally collects her courage and confesses to him, he bluntly turns her down. When an earthquake strikes Tokyo, her house is the only one damaged. A friend of Kotoko's father jumps at the opportunity to lend a hand, and in a surprising turn of events they end up living at Irie's house.

While walking to school together, Irie tells Kotoko that he doesn't care for her, and when Kotoko is pushed off the train at the wrong station Irie does not help her, saying he hates absent-minded girls even more than stupid ones.

Kotoko falls asleep with a confession letter in her hand. When Irie walks in to tell her it's her turn in the shower, he impulsively decides to read the letter. Later at the school sports festival, Kotoko and Irie end up competing against each other.

Kotoko, Irie and friends visit Waterland. While Irie's getting ice cream, Yuuki ends up sinking in the pool, and Kotoko saves him. Irie overhears about the rescue, rushes back to Yuuki, and is pleased at Kotoko's actions.

The final exams starts next week, and the results decide whether or not the F-class students make it into college. After having received prior assistance from Naoki with her and her friends' schoolwork, much to Irie's annoyance.

It's Valentines Day soon, Irie's mother helps Kotoko make homemade chocolate, but Kotoko fails to give them to Irie. Later on, Naoki goes to take the entrance exam to Tokyo University.