Keitaro Urashima is a 19 year old loser. He is a second year ronin (a student who has failed their college entrance exam) and has been kicked out of his parents' house. He is desperate to get into Tokyo University due to a childhood promise he had made to a girl. He comes to his grandma's inn to stay and study, but when he arrives, there's no one around. Keitaro decides to relax in the open-air bath, when a woman walks in on him. She starts chasing him through the building and is soon joined by the other residents. Finally Keitaro's Aunt Haruka comes to his rescue and reveals that the inn has become a girls dorm and Granny Hina is on a world tour. Haruka is under the impression that Keitaro is actually a Tokyo U. student. Keitaro does nothing to dissuade to her and the other residents of the dorm are impressed and decide to allow Keitaro to stay.
Later, Naru (the girl who walked in on Keitaro in the bath) tricks Keitaro and discovers that he is not really a Tokyo U. student. She decides not to tell the others because Keitaro had given Shinobu the confidence to work on her grades. The other girls walk in on Keitaro and Naru in a compromising position and in the ensuing chaos, Su discovers Keitaro's prep school ID. The residents of the dorm, upset about being lied to, kick Keitaro out. He tells Haruka that he is going back home, but Haruka tells him that's not possible. Granny Hina has just sent a fax.
Keitaro is the new landlord of Hinata House.
The residents of the dorm are angry and decide to make so Keitaro so miserable he'll have no choice but to leave. They make him do all the chores and bathe in a bucket. At first Naru feels sorry for Keitaro, but after several incidents of him accidentally peeping on her, she decides to help. Keitaro overhears their plans and decides to stay.
Keitaro rushes off to prep school and meets his friends Haitani and Shirai. They discuss a fellow classmate who just happens to be first in the nation. Keitaro bumps into her and he apologizes. The girl reveals herself to be Naru. She wears glasses and looks different at school to concentrate on her grades. Throughout the day, Naru and Keitaro are forced to sit next to each other during class and eat lunch together. At the end of the day, they come home together which causes some consternation among the other roommates.
Keitaro is having problems studying and decides to ask Naru for help. After a couple of attempts and turning him down, Naru finally agrees. Naru asks him why he is trying so hard to get into Tokyo U. Keitaro tells her about the promise he had made, and askes Naru if she thinks the girl even remembers. Naru gets very starry-eyed and says the girl would absolutely remember. Kitsune knocks on Naru's door and wants in. Keitaro hides under the kotatsu(heated table) so Kitsune won't get the wrong impression.
Shinobu is still upset after being lied to by Keitaro. Haruka suggests looking through Shinobu's file to see if there's a way Keitaro can make it up to her. His first few attempts are disastrous, but then Keitaro realizes that it is her birthday and throws a surprise party for her. The other residents tell Shinobu that it was Keitaro's idea and she forgives him.
Keitaro, Haitani, and Shirai are walking home after school when they try to holler at some girls. The girls turn out to be Naru, Motoko, and Su. Motoko uses her umbrella and knocks the three guys out. Back at the dorm, Keitaro asks Naru why Motoko hates him so much. Naru tells him that Motoko is the daugher of a famous kendo master near Kyoto. After several scenes of Keitaro embarrassing Motoko, Motoko realizes that she isn't feeling well. She is light-headed and has trouble breathing. Afraid that she is falling in love with Keitaro, she challenges him to a duel. The duel ends with a tie with them both collapsing; Keitaro from fright and Motoko from a cold. The chapter ends with Motoko glad she's not in love, and Keitaro glad he's still alive.