Los Angeles is enduring a heat wave and a crime wave, so the pressure on police officer Michael Harrigan (Danny Glover) to solve a strange string of murders is mounting. Harrigan thinks the culprit can be found among the warring gangs and drug cartels, but FBI Special Agent Peter Keyes (Gary Busey) knows the horrible truth: Their killer is a fearsome extraterrestrial (Kevin Peter Hall) with keen hunting abilities that include superior night vision and the power to make itself invisible.