Mike Harrigan is a cop with the LAPD.
As is shown in the movie, he is a headstrong and calculating policeman, violates orders which he sees are messy. He jumps into action, isn't afraid to provide cover for his team. And he has a knack for action.
Following a search and capture operation during a gang-war, his team senses something amiss. Someone seems to have gotten to their targets before them, and has literally butchered them. As more such incidents follow, Harrigan decides to visit the local "powder prince", King Willie. Willie tells him that an unknown and powerful force is behind the murders of the policemen and the gang members.
Harrigan loses his best friend Danny, to the Predator. After some hot talks with a special agent, Keyes, he loses another man of his team when the Predator attacks a metro-rail. Going to Danny's grave, he catches sight of Danny's necklace hanging from a tree. He knows that he is being followed by the killer.
One night, he sees the Predator and follows it. After a lengthy chase, the Predator stops at a slaughterhouse. But Harrigan is intercepted by Keyes' men and brought to their mobile base. Keyes tells him that they have been keeping tabs on the Predator for some time, and have devised a way to capture it. The special agents dress up in special suits and go into the slaughterhouse. However Harrigan notices the Predator's cautious movements and knows that the agents have lost their cover.
Soon after the Predator kills all of the agents, Harrigan engages in a one-on-one fight with it and manages to wound it with his big guns. But the Predator refuses to be put down, and kills Keyes who seemingly had survived the Predator before. They make their way to the rooftop and Harrigan pushes both of them over the ledge. As the Predator arms his nuclear bomb, Harrigan uses the Predator's cutter disc to disarm the bomb and cuts off the Predator's hand.
The action shifts to the next building and into the Predators' spaceship. Inside a grand chamber, the Predator engages Harrigan, but Harrigan still wins, using the Predator's own weapon against it. Other Predators come and take away their fallen comrade, and gift Harrigan with an antique flint-lock gun. Their spaceship blasts away, leaving Harrigan on the ground.
The special agents arrive too late, but Harrigan anticipates that the Predators will return.