From MangaHelpers:

Azumaya Kotori was a typical teenage girl who went to school, hung out with friends, and had a crush on a boy. One day, she gets hit by a truck and dies, but her spirit still wanders this dimension.

The boy Kotori has had a crush on, Kusakabe Aruto, is unusually spiritually attuned and so can see her spirit. Aruto discovers that Kotori is not really dead; she's in a coma. Her soul, her current form, has escaped from her comatose physical body.

To get back to normal and revive from the coma, she has to find a way to rejoin her body and her spirit. In the meantime, Kotori ends up staying under the same roof as Aruto and his family, who can all see her. Although the circumstances aren’t ideal, Kotori is delighted and nervous about spending intimate time with her crush. [vyc]