15 years ago, Urashima Keitaro, made a promise with a girl that they will enter Tokyo University and find happiness together. 15 years after, he has failed his second retake of the entrance exams. One morning he receives a call from his grandmother to go to Hinata Lodge, the same place Keitaro had made the promise with the girl 15 years back.
Upon arriving, to his surprise Hinata Lodge is no longer an inn, but is now an all-girls dormitory. To make matters worse, he was made the manager of the dormitory against the disapprovals of all the tenants. So now, he finds his grandmother gone and himself under attack by all-female residents! Will the girls accept him as their new apartment manager? Will his bones ever knit? More importantly, can he concentrate on his studies when he discovers one of his tenants might be his long lost love...