Following a terrible road accident Agata is left in a coma - and twin sister Catalina begins to experience the pain and terror that her unconscious sibling is going through... Catalina is compelled to solve the mystery of her twin sister's accident at highway Km31.

Following a series of terrifying events, Catalina feels their psychic link growing stronger and that Agata is screaming for help from her unconscious state. With help from friends and a police investigator, they uncover a legacy of violent deaths and mysterious disappearances. They discover tales of vengeful ghosts and malign spirits that prowl Km31 and who are said to prey on travellers... It seems that Agata is trapped between life and death, between reality and a terrible netherworld of evil spirits and ancient legend.