Naomi Yuiki, 21 years old single, college student. Though her parents died, because of the inheritance she and her brother, Kouta Yuiki age 18, can live without much trouble.

Even though she is 21 she is still a virgin because secretly in love with her younger brother. Even her attempt to get over him by sleeping with Takuya Yoshizawa, a genius surgeon and once a subordinate of her fathers didn't work and that depressed her even further.

At that time she met with an accident. A traffic accident so severe that her whole body except her brain is ruined beyond salvation. Just as doctors were about to give up on her an another patient at the same hospital, Akane Kitahara suffers brain death. Taking this chance, Yoshizawa who was working on advancing the research on the brain transplantation decides to transfer Naomi's brain to Akane.

Naomi's new life as Akane Kitahara starts. This time Naomi is not restricted by morality of a brother and sister relationship, but things don't go as easy as she hopes because being Akane brings her own relationship problems. Chaos ensues...