The film Men in Black: International follows the story of Molly, a young woman who has spent her entire life searching for proof of extraterrestrial life after witnessing an alien encounter as a child. Her determination eventually leads her to discover the hidden headquarters of the Men in Black in New York, where she impresses the agents with her intelligence and persistence. Given the codename Agent M, she is assigned to work under the supervision of the London branch, a location known for its elite reputation and high-risk missions that require both experience and instinct.

Upon arriving in London, Agent M is paired with Agent H, a once-legendary operative who has grown reckless and overly confident after a major mission that made him a hero. The two form an uneasy partnership, clashing in personality but forced to cooperate when a powerful alien threat emerges. A mysterious species known as the Hive begins infiltrating Earth, displaying abilities far greater than anything the organization has faced. Their powers suggest they can mimic and possess other beings, creating confusion about who can be trusted.

As M and H investigate a series of escalating attacks, they discover that a pair of alien assassins are searching for a highly destructive weapon hidden on Earth. Their mission takes them across multiple countries, from glamorous parties to remote deserts, all while dodging enemies who seem to anticipate their every move. Slowly, the partners realize that someone within the Men in Black itself may be leaking information or secretly working with the enemy, raising the terrifying possibility of a mole inside the agency.

The situation worsens when they learn that the London branch leader, High T, is acting strangely and may be connected to the threat. Doubt, suspicion, and secrecy begin to drive a wedge between M and H, yet their growing respect for each other pushes them to keep digging. As they get closer to the truth, they uncover a conspiracy involving past missions and rewritten memories, revealing that the Hive may have already infiltrated the organization at its highest level.

With time running out, M and H must put aside their differences and use the weapon meant to destroy the planet to stop the Hive from completing its takeover. Their final confrontation exposes hidden loyalties, tests their courage, and forces them to rely on trust rather than reputation. In the end, the two agents succeed not because of their skills alone but because they combine M’s sharp intuition with H’s experience, proving that the Men in Black can still protect the galaxy—so long as they work together.