Mio works as a nurse at a hospital in Tokyo. She has always wanted to be a doctor and this is her first steps towards her cherished dream. Takuya hasn't seen his childhood friend Mio for years and finally meets her... However, she inadvertently slipped right on the stairs and he broke his arm saving her. Takuya was placed in the therapy room where Mio worked. She felt guilty towards him because of the stupid accident. And Takuya, to cheer the girl up - said he'd be happy if she'd take care of him in her spare time. But Mio took his words too seriously and "responsibly"