The girl Nam befriends the bullied boy Thongsook at the same room in the hospital and she tells that she likes horror films. Thongsook asks whether she would like to see ghosts and he removes his necklace with an amulet and is attacked by ghosts. Years later, Thongsook is an outcast teenager that studies in the same class of Nam and has a crush on her. When Nam and her friends Boy, Jack and the lesbians Beam and Pui decide to spend a night in an infamous island, they do not tell Thongsook. The boatman warns the group that the place is cursed and they should neither stay there nor visit the sanctuary where a tragedy happened but they do not pay attention to his words. Meanwhile Thongsook finds their map and meets his mates in the island. Boy, Jack and Beam force Thongsook to go with them to the sanctuary and he tells that the place is evil. However Boy and Jack take his amulet and lock him up in a cell to scare him but they can not open the padlock. They go home to bring a crowbar to open the padlock but they party instead and Thongsook spends the night in the sanctuary. On the next morning, Nam finds the amulet in the house and they go to the sanctuary to release Thongsook. However they do not find him. They ask the boatman to come back on the next day and he warns that they should not spend the Friday 13th in the island. What might have happened to the teenager?