Attempting to fulfill a promise to his childhood sweetheart, Keitaro Urashima is determined to enter Tokyo University. After being rejected twice, he decides to leave home and stay at his grandmother's apartment complex to study. But when he arrives, his grandmother is gone and he finds himself under attack by the all-female residents. Will the girls accept him as their new apartment manager? Will his bones ever mend? More importantly, can he concentrate on his studies when he discovers that one of his tenants might be his long lost sweetheart?