Mio works as a nurse in a hospital in Tokyo. She always wanted to become a doctor and these are her first steps to the cherished dream. Takuya has for many years not seen his childhood friend Mio and now he finally met her... However, she inadvertently slipped right on the stairs and he was saving her, broke his arm. Takuya was placed in the therapy room where Mio worked. She felt guilty about the stupid accident. And Such to cheer up the girl-said he would be happy if she would take care of him in his spare time. But Mio took his words too seriously and "responsibly".