Based on the true story of New Zealand's biggest mass killing, this riveting docudrama recounts the violence of gunman David Gray, who inexplicably opened fire on 13 residents of a sleepy seaside community on Nov. 13, 1990. Centering on several terrified citizens' exceptional valor, director Robert Sarkies conveys a realism that intensifies the chaos and horror of the 24-hour ordeal. Matthew Sunderland plays the unhinged, cold-blooded Gray.