A group of deadly assassins kidnap a hostage in the hope of getting a high ransom but when they manage to lose themselves in a forest and end up spending the night in a haunted house they manage to disrupt the plans of the ghosts to descend to heaven. The assassins hatch a plan to solve the problem but in doing so reveal themselves to be incompetent, so the ghosts decide to give them some training themselves…

At Sunjong University, a few students are serious, including Eun-hyo, who works hard at aerobics in hopes of doing well in a national competition. Most students goof off: drinking, partying, and focusing on sex. Eun-shik, a law student who’s been in the military, is older but socially inept. He likes Eun-hyo; even though his earnest and simple side appeals to her, his juvenile excesses make him irrelevant when Sung-ok, a good-looking rich kid, charms Eun-hyo. They begin an affair, leaving Eun-shik on the sidelines. The national competition approaches and complications arise.

While investigating the school files, the frightened teacher Mrs. Park startles and calls the young teacher Eun-young Hur, telling her that the deceased Jin-ju Jang is back. The line dies and Mrs. Park is attacked and killed by a ghost. On the next morning, the teenager Jae-yi Yoon waits for her friend Ji-oh Lim, who has the ability to call the spirits, and they begin a close friendship. The abusive and aggressive Mr. Oh, a.k.a. Mad Dog, is the substitute of Mrs. Park and prohibits Ji-oh to paint and compares the performances of the pretty So-young Park and the weird Jung-sook Kim, raising a barrier between the two former friends. Miss Hur misses her former friend Jin-ju, who committed suicide, and while trying to contact her, she discloses a dark secret about the past of her friend and Mrs. Park.