A relentless marketing executive and a warm-hearted intern are always at odds with each other but everything takes a wild turn when their souls switch after an unexpected kiss.

A boy falls to his death at school, but Ok Chanmi does not believe that her twin brother, Park Wonseok, committed suicide. Chanmi transfers to her brother's school, Yongtan High, and meets Ji Sooheon, who witnessed her brother's death.

A high school becomes ground zero for a zombie virus outbreak. Trapped students must fight their way out — or turn into one of the rabid infected.

Three horror stories, with each set in the past, present and future.