Moving into her first apartment, Sayaka invites her friends to come over to celebrate. During the party, she begins to behave strangely and suddenly runs to the balcony and plunges to her death. At her funeral, her friends to believe this was a suicide. Her sister Mariko discovers Sayaka wasn't the first to plummet to her death. As she begins to uncover the shocking history of Apartment 1303, she comes face-to-face with an evil more powerful and terrifying than she could ever have imagined.