While combing through the belongings of his recently deceased aunt, Matsuko, nephew Sho pieces together the crucial events that sank Matsuko's life into a despairing tragedy.

High school students go on a graduation trip. They become gripped with fear by the spirit of a dead classmate. Their classmate committed suicide on Valentine's Day, one year ago. She left behind the words "Let's meet one year later." The students must overcome their fear and find out the truth behind the tragedy that took place one year earlier.