A walk down memory lane of school memories filled with studying and bullying. After graduation, each student who was a senior of Class 5 receives a message to participate in an alumni reunion. No one knows who sent the message. A reward of $10,000 and the location is an abandoned island. Although there were some suspicious parts to the message, everyone participates, thinking that it was a joke. In this event, everyone relives and faces their past self which they had buried for so long.