It was a rainy night, a girl in uniform named Takada Mitsuru suddenly visits the house of Atsutaka Satou. That day, as she came back from school, her house was already someone's property. Due to family-circumstances, she was passed to many different relatives, but ended up homeless. She seeked Atsutaka for help because of the close relationship their late-mothers had which they promised to help each other.
Atsutaka was suddenly put into a situation where he has to live with a girl. He hopes that he can get close with her little by little.