Books in the Inside Mari series

Mari's life is starting to fall apart. She's fallen out with her friends, teachers and family. So, with few clues as to where she has disappeared to, Isao and Yori turn their focus on the man currently living in the Komori apartment.

A college student apparently wakes up in the body of a high school girl.

With an unexpected clue, Yori and Isao wait for further contact from Mari. Unfortunately, neither one of them is strong enough currently to handle this sudden turn of events. Their next step will be to settle their differences with the hope that they'll better understand Mari's troubles.