The earth is not just the world of humans. In fact, there are 1500 aliens living among us, and the Interstellar Immigration Bureau handles matters related to aliens. New York ordinary police officer Edwards (Will Smith) joined this organization by chance and became a member of the MIB, code-named J. Since then, he has no name or identity, and has become the partner of Special Police Officer K (Tom Lee Jones). The first incident J responded to was an invasion of the Zerg. Prince Rosberg of Aguilan was killed by the Zerg on Earth, and the "Galaxy" he carried with him-the best source of subatomic energy in the universe-has also disappeared. If the Zerg found it, it will bring a devastating blow to the Aguilans; the Aguilans issued an ultimatum that if the people of Earth could not hand over the "Galaxy" within an hour, they would destroy the Earth. For the safety of the earth, K and J had to stand up.