Hyo-shin (Yeh-jin Park) and Shi-eun (Young-jin Lee) are two girls in love in a Korean high school. They share a journal together, taking turns writing in it, and can even communicate with telepathy. But there is talk of suicide after a very public display of affection and difficulty with other students leads to some wariness on Hyo-shin's part. Eventually, one jumps from the roof of the school ... or was she helped to her death?

Then things get freakier. Fellow student Min-ah (Min-sun Kim) finds the journal and begins to see visions and hear things. A friend accuses her of dating Shi-eun. Is everyone who reads the diary bound to die?

For the most part, the film is a confusing mishmash of images, dialog and overly dramatic music in a non-linear timeline. Midway through the story of teenage girls, it turns into a horror movie with ghostly images of the lovers, but returns to flashbacks of the two when they were alive. Then back to the horror movie again for the end, with heavy doses of annoying teenage girls who do know how to scream.

Regardless of its entrance into the horror genre, Memento Mori fits squarely into the tragic lesbian love story in which one of the lovers must die out of shame.