The film is based on the Aramoana massacre that occurred over a period of two days in mid November 1990 in a small seaside settlement in the Otago region of the South Island of New Zealand. The small coastal community of Aramoana (Māori for "pathway to the sea") lies on the edge of the Pacific Ocean at the base of a narrow sandy spit which juts into the mouth of Otago Harbour, 27 kilometres northeast of the city of Dunedin. The settlement is normally a peaceful, idyllic locale, but in 1990 the community was turned upside down as a result of the country's worst massacre prior to the Christchurch mosque shootings. Resident David Gray, an unemployed gun enthusiast, went on a shooting spree, killing 13 people before being killed by police.