The quiet, seemingly-idyllic life of Lake Tutaikure, New Zealand, is disturbed when a group of tourists (American horror movie stereotypes: The Jock; The Pretty One; The Ethnic Minority, etc...) are found dead after skinny-dipping at midnight.
Charged with solving the unusual crime scene - the victims have all bled to death and are missing various limbs, apparently eaten away be an animal - is Rua Tuapene.
Rua is the Community Constable of his home town and this case is way out of his league. He enlists his cousin, Hemi, a local Department of Conservation worker, to try and find out what kind of animal killed the victims. Rua and Hemi are joined in the investigation by Eraita, daughter of the one of the local kaumatua (village elders). Together, they investigate the possibility that a breed of carniverous eels are the cause of the deaths. According to local legend, these eels are the result of an unhappy spirit, feeding on the innocent. Hemi is not convinced, speculating that pollution from nearby farms has caused some sort of genetic mutation in the lake's eel population...but then again, Hemi smokes a lot of weed.
Whatever's the cause, the body count continues to multiply, leaving Rua in a race to solve the mystery, before Lake Tutaikure becomes the one place in New Zealand no one will ever want to visit...