A group of Internet chatters decides to spend the summer together at a beach, renting an apartment and trying to know each other for real (or maybe they just want to have sex). Apparently a guy named "Sandmanz" committed suicide when he was ousted from the chatroom, and the group has split opinions on the matter. Some think he was just a psycho with no life, and he had it coming. Some others, like Yoo-na (the one who got closer to him), think that someone spread lies to force him to quit. Suddenly, the group is decimated by a mysterious figure who keeps e-mailing everyone that his/her fate will not be unlike Sandmanz's. The search for the killer begins, while people die right and left. (lovehkfilm.com)

在碾米廠工作的石九，是一位只有8歲智力的30多歲青年。某日，他遇到被誤會是扒手的離家少女恩智。為了找出真正的犯人，兩人決定結盟成為彼此好友。不過恩智的老師卻擔心精神狀況不穩定的石九，可能會對恩智造成危險；反觀照顧石九的神父則說不會發生這樣的事。某晚，恩智發生事故，而矛頭似乎指向了石九…。