Manga: When he was a child, Keitaro Urashima promised with a girl that they would meet in Tokyo University (Toudai). For this reason he has tried to get into the prestigious university, but has failed the entrance exam two years in a row. When his parents kick him out of the house he tries to find lodging at his Grandmother's inn, but unbeknownst to him it has been changed into an all-girls dormitory. He is allowed to stay in the position of kanrinin (dorm manager) but his clumsiness tends to land him in trouble with the girls. To achieve his dream, he studies to pass the Tokyo University exam along with Naru Narusegawa, who has her own reasons for wanting to get into Toudai.
Anime: Keitaro Urashima is determined to be accepted into Tokyo University, the hardest Japanese University of all to get into, because of a promise he made to a girl when he was young... a girl whose name he can't even remember. After failing to get into Tokyo U twice, he is kicked out by his parents and goes to live with his Grandmother at her hotel, but it seems it has been turned into an all girls boarding house. What's more, much to his surprise and to the tenants disgust, Keitaro is made manager of the boarding house.
(source: ANN)