Fifteen years ago, Keitaro Urashima met a girl and promised her to enter Tokyo University together. To keep this promise, he is now preparing for another entrance exam, although he has already failed twice. One day, he visits his grandmother's Japanese-style inn. But this inn has been changed to girls' dormitory "Hinata-sou".

Shinobu Maehara is a junior high school girl. Her family is now getting ready to move out of the town, but she doesn't do her packing at all because she is unwilling to move. She runs away from home and is sitting on a bench, getting so depressed. She finds a sketchbook at her feet and sees her cute smiling face being drawn inside. To return this sketchbook, Shinobu visits Hinata-sou.

On the way home from a cram school, Keitaro and his friends go up to town and pick up four high school girls. But one of them has a bamboo sward and she thoroughly beats them up. After having such a hard time, Keitaro returns Hinata-sou, gets into a laundry room and sees the girl with a bamboo sward, Motoko, there.

It is revealed that Keitaro is not a Tokyo University student. He humbly begs their pardon. He is forgiven on conditions to be a good caretaker and to pass the exams for Tokyo University. But he is pushed around to do cooking, laundry, and house cleaning, so there is no time to study at all. One day, he asks Naru to teach him study.

The day of the secondary exam for Tokyo University comes. Keitaro wants to pass the exams with Naru, while she ignores him and devotes herself to her wordbook. They are given a hearty send-off by friends in Hinata-sou, but accidents happens one after another, such as going the wrong way, losing an admission ticket for an examination. Can they ever reach to the site for the examination?

Every one in Hinata-sou worries whereabouts of Keitaro and Naru. Keitaro and Naru are travelling in Kyoto to overcome their disappointment, after finding that they both have failed the exams. At Kyoto station, they meet Mutsumi, a girl who met them at the examination room and also fails the exams.