Watch Men in Black for Free: How to Stream the Movie Online at 123Movies. . 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 K and new recruit Agent J 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.