Shortly after the mysterious death of sixteen year old Alice Palmer, her family summons a psychic and a parapsychologist into their home and discovers that the secretive teen had been leading a double life. Alice was swimming in a local dam when she drowned tragically. Later, after her body is recovered and the coroner issues a verdict of accidental death, Alice is laid to rest and her family returns home to grieve in peace. The Palmer's mournful silence is short-lived, however, when a series of strange occurrences in and around their home leaves them convinced that they are experiencing something supernatural. Seeking the advice of a psychic and a parapsychologist, who reveals that Alice had been keeping some profound secrets from her friends and family, the Palmers travel to Lake Mungo and begin unraveling the mystery of the troubled adolescent's double life. A faux-documentary shot in the style of The Blair Witch Project and Diary of the Dead, Lake Mungo proves that the mysteries of the living don't lie silent with the deceased.