Lin McAdam rides into town on the trail of Dutch Henry Brown, only to find himself in a shooting competition against him. McAdam wins the prize, a one-in-a-thousand Winchester rifle, but Dutch steals it and leaves town. McAdam follows, intent on settling his old quarrel, while the rifle keeps changing hands and touching a number of lives.
After a police chase with an otherworldly being, a New York City cop is recruited as an agent in a top-secret organization established to monitor and police alien activity on Earth: the Men in Black. Agent Kay and new recruit Agent Jay find themselves in the middle of a deadly plot by an intergalactic terrorist who has arrived on Earth to assassinate two ambassadors from opposing galaxies.