This film like so many in Japan deals with the unexplained (and apparently very popular phenomenon of the ghosts of people returning to their loved ones.
The actors do a surprisingly good job even if they aren't perhaps the best people for the job, however their contribution is not enough to overshadow the lack of plot, slow pace, poor direction and horribly cheesy writing.
Interestingly, nobody I watched the movie with seemed to be bothered by the fact that the main girl is just that... a girl and very, very much underage.
The only real reason to see the movie is if you are a fan of the musician who plays the main character as he performs several songs made just for this movie which are -unlike the rest of the movie- very impressive and emotional.