Firstly,

This is a psychological movie, the main part is the dark side.
So if you want to watch just some bright movie about friendship, this is not the right one.

The movie starts with two high school girls dealing with some teen problems, seems cliche. But as the story develops it gets more and more creepy. Not the creppiness of an horror movie , but a psychological one. The final part is the climax, turning this into a disturbing story.

If you like psychological, it's worth to watch.

WATCH the part after the credits , you can figure out what really happened, or you can get more confused.