The Men in Black have always protected the Earth from the scum of the universe. In this new adventure, they tackle their biggest threat to date: a mole in the Men in Black organization.
Molly Wright has been obsessed with finding the Men in Black ever since they came by her house as a child, and she met a real alien. As an adult, she finds the agency and convinces Agent O to let her in. Molly becomes Agent M and is sent to London to team up with Agent H to stop a threat from a destructive alien race known as The Hive.
M is given a crystal from an alien named Vungus that turns out to be a compressed star that has been made into a super weapon. On their mission, they are joined by a small alien named Pawny, who pledges allegiance to M as his new queen after his original one is killed. Searching for it are the Dyads, twin shapeshifters that drain organic matter of energy. The MIB, led by High T, destroy the Dyads, but the agents realize that T has been a mole in the agency, and he has been wanting to get his hands on the crystal after being infected by a Hive alien during his and H’s previous encounter with them.
M and H fight T in the Eiffel Tower after he morphs into a Hive alien trying to use the crystal to destroy planets. M gets her hands on the crystal and destroys both T and The Hive’s entire base.
The two agents are promoted and later joined by Pawny in further adventures.
Twenty years ago, Molly Wright witnesses her parents being neuralysed by agents of Men in Black (MiB) while she helps an alien escape, avoiding neuralysation herself as her parents assumed that she was asleep. Years later, having been rejected in applications to the FBI and the CIA on the grounds of her “delusions” regarding the evidence of alien life, she manages to track down an alien landing and track the MiB agents back to headquarters. Although she is caught upon entering the agency, Molly makes such an impression on Agent O, arguing that she has proven her skills in finding out about the organization’s existence and has no life outside of her search for the agency, that she is accorded probationary agent status as “Agent M” and assigned to the London branch of the organization as a probationary agent.
Once in London, M meets High T, the head of the London branch, and manages to arrange for herself to be assigned to assist Agent H in his meeting with Vungus the Ugly, a member of an alien royal family who has a long-standing history with H. During their night out with Vungus, they are attacked by mysterious alien twins who can manifest as pure energy, who seriously wound Vungus. Vungus passes a strange crystal on to M before he dies, claiming that he cannot trust H with it as H has changed since they last met. Although Agent C expresses disdain for H’s actions, M points out that few people knew Vungus’ location when he was attacked, which leads to the conclusion that Vungus’ location was betrayed by one of the MiB agents present when High T assigned H to guard him. Reeling at the implications of a traitor in MiB itself, High T assigns C and M to conduct an investigation while H is relegated to desk duty, with the investigation suggesting that the twins had DNA traces of the Hive, a parasitic race who invade other planets by merging with the DNA of the conquered species. M learns that H and High T were responsible for driving off a Hive invasion at the Eiffel Tower in 2016, using a wormhole included in the original migration to Earth, but since that time H has essentially declined, demonstrating a lax attitude towards his duties and apparently only keeping his job due to High T covering for him out of respect for his past.
H convinces M to join him in following up a lead in Marrakesh, where they recover “Pawnie”, the last survivor of a small group of aliens who were attacked by the twins. Pawnie pledges new loyalty to Agent M, but they are subsequently attacked by MiB agents coordinated by C, who has recovered video footage of Vungus passing the crystal on to M and believes that she is the traitor. With the aid of one of his alien contacts, H is able to acquire a rocket-powered bike and escape with M and Pawnie, where they learn that the crystal Vungus gave M is actually a weapon powered by the fragment of a dwarf sun. As they repair the damaged bike, H’s alien contact manages to steal the weapon and take it to Riza Stravos, an alien arms merchant with whom H has a past relationship.
Traveling to Riza’s island fortress, the trio attempts to infiltrate the base and recover the weapon, but are caught by Riza and her bodyguard. However, the bodyguard turns out to be the alien that M rescued as a child, and he returns the favour by allowing them to leave while he keeps Riza contained. The three are attacked by the alien twins once again, but the twins are killed by High T and a group of agents.
Although the case appears to be concluded, H and M review the evidence and realize that the twins’ phrases could suggest that they required the weapon to use against the Hive rather than to use it for the Hive, especially when the only evidence of Hive DNA was provided by High T. As Agent C concedes that the evidence favours the idea of High T’s deception, he allows H and M to follow High T to the Eiffel Tower. As they travel to the wormhole, M’s questioning of H’s memory of his defeat of the Hive reveals that he was neuralysed, which is confirmed when they confront High T; the Hive converted High T into one of them and neuralysed H so that he could act as the ‘hero’ and conceal their true activities. The High T/Hive “hybrid” is able to activate a wormhole that will draw the Hive to Earth, but H is able to draw out High T’s true personality long enough for M to use the weapon to destroy High T and the Hive infestation trying to reach Earth through the wormhole.
With the truth of High T’s conversion exposed, Agent O joins H and M in Paris, where she accords M full agent status and appoints H probationary head of MiB’s London branch.
Paris, 2016 – Men in Black Agent H (Chris Hemsworth) and London branch director High T (Liam Neeson) arrive at the Eiffel Tower to take out an alien invasion from the creatures calling themselves The Hive. If unleashed, they can wipe out everything in their path. After neuralyzing and shooing away a couple, H and T fight their way into a passage in the tower that leads to The Hive’s base of entry. The agents arms themselves as the doors open, and the creatures emerge from the other side.
We jump back 20 years earlier in Brooklyn where little Molly Wright (Mandeiya Flory) watches as two MIB agents talk to her parents outside as they are looking for a creature known as a Tarantian. Unbeknownst to them, the creature is in Molly’s room, but she sees it as adorable and harmless. The agents neuralyze Molly’s parents, but this moment changes her life.
As an adult, Molly (now played by Tessa Thompson) has been going through different agencies trying to uncover the secret organization that she has been obsessed with finding since that fateful night, all while working a dead end desk job. She catches a reading of an anomaly on her computer, and she follows the reading to a street in New York where a hidden entry is uncovered when pigeons fly through but disappear. Molly enters and watches MIB agents at the scene of an alien sighting. She finds a suit and tries to sneak in to the MIB headquarters, but she is scanned and identified as an unknown intruder. Molly is then met by Agent O (Emma Thompson) when the other agents take her in and attempt to neuralyze her. She saves herself by revealing that she knows all about them after what she saw, and she must have some qualifications to join since SHE found THEM. O is unconvinced until Molly says that she has no life and nothing to live for, and uncovering the truth might give her a purpose. O decides to allow her in as a probationary agent and gives her all that she needs to now become Agent M.
In London, H is attempting to catch a known alien gangster during a card game, but he is outed as an MIB agent, and things get out of control as a venemous three-headed worm is set loose upon the place. The other aliens are killed, and both H and the head gangster are bitten, with the gangster’s assistant holding the antidote. H convinces her he will give her anything for the cure…so they sleep together.
Two alien creatures from the race known as Dyads (Laurent and Larry Bourgeois) arrive on Earth and steal a man’s identity after killing him. They encounter small aliens of the Pawn race and order that their queen be sacrificed. The queen’s protector, Pawny (Kumail Nanjiani), attempts to defy the Dyads, until they make ther seriousness known.
M is sent to London via MIB’s special subway. There, she meets High T and learns of MIB’s monitoring alien activity from areas far outside the U.S., and they have been made aware of the Dyads’ arrival on Earth, and as they are from a planet close to The Hive, the agents fear they may strike again. M soon sees H as he enters a meeting where T tells the agents that a member of the Jababian royal family, Vungus (Kayvan Novak), wants the agents to show him a good time. H is assigned to be Vungus’s chaperone, and M manages to get herself in as his partner to join him on the case.
M and H go to a nightclub to meet Vungus. H attempts to hook M up with Vungus, but she refuses. The Dyads show up there and infect Vungus with some kind of poison. As his guards bring him out with the agents following, Vungus’s car gets blown up in the street. The Dyads emerge and attack, so M and H break out the big guns to fight back. However, the aliens prove to be almost unkillable, as the just absorb whatever energy the MIB hit them with. M goes to Vungus, who gives her a small crystal to keep in her protection. He doesn’t trust H and thinks there’s a threat within the MIB, and he dies soon after. The Dyads disappear, and the agents are met by Agent C (Rafe Spall), who chews them out for the disastrous outcome.
M and H meet with C and T in the aftermath. C suggests they fire and neuraylze M, but H defends her. She brings her suggestion to T that someone in MIB could be a mole. T has more doubts in H’s capabilities, as everyone thinks he isn’t the same agent he once was. M and H then investigate the poison that Vungus was injected with, as H knows where it can be found. Meanwhile, C is shown surveillance footage of M in possession of the crystal.
The agents travel to Marrakech where they find Nasr (also Kayvan Novak), a known dealer who has a living alien beard named Bassam (ALSO Kayvan Novak). They bring up H’s relationship with a notorious alien arms dealer named Riza (Rebecca Ferguson). After the agents leave them, Nasr and Bassam spot the Dyads walking by. Nasr then orders Bassam to call Riza.
M and H come across a shop where they find a dead body and a secret entrance where they find the dead Pawns, save for Pawny. After the queen dies, he overdramatically tries to kill himself, but M convinces him to help them since he is a witness, and Pawny pledges allegiance to M. They leave, and H shows M that he took the crystal from her, and he’s disappointed that she didn’t trust him enough to let him know. They then spot MIB agents approaching them as they were sent by C. They run back to Nasr and are given a hover bike to get them through the crowd. They escape the town but crash into the desert. T finds C’s tactics unethical and makes him consider that he is the mole. C thinks it’s H who can’t be trusted, but T still has faith in him.
The three discover that the crystal is a super-compressed star that has been designed to be a powerful weapon of mass destruction, which could prove deadly in the hands (or tentacles) of The Hive. They witness its power at the lowest setting when M accidentally activates it and makes a canyon in the sand. They set up camp for the night and bond for a bit until they find that Bassam stowed away in their canteen, and he steals the crystal to take to Riza. The agents and Pawny fix the hover bike and fly to Riza’s fortress.
Upon arriving, H uses Pawny as a peace offering and trade for the crystal to Riza. She is still hung up on their break-up, and so she double-crosses H and tries to have him sent off the island by her henchmen. However, H fights them off and runs back. M makes her way into the fortress and fights Riza while H fights her Tarantian bodyguard Luca (Spencer Wilding). Riza orders him to kill them until M learns he is Tarantian, and she repeats a phrase that the little Tarantian taught her as a child. Luca realizes who M is, and he turns on Riza, but the agents let her off once she gives them back the crystal.
As the agents prepare to leave, H tells M that his real name is Henry. Soon, they are cornered by the Dyads. H vows to protect the planet from The Hive, to which the Dyads reply that they are as well. MIB agents then show up and vaporize the Dyads with high voltage weapons. T comes out and congratulates the agents on their success.
The other agents celebrate the victory, but M and H feel that something is suspicious after the Dyads indicated they were never working with The Hive. After their case file is found to be deleted, M, H, and C all begin to realize that T might be the actual mole in the organization, but they need to keep it on the low and stop whatever he has planned. M, H, and Pawny take a car-ship-vehicle out and head to find him.
C guides the agents to a portal from The Hive has been opened in a nearby sector, in the Eiffel Tower. As they head to the site, M asks H how he and T first beat The Hive, but he only repeats the same exact phrase that has ever been used in describing the event (“with nothing but our wits and Series 7 deatomizers”), leading them to realize that H was neuralyzed and that The Hive infected T before going into hiding and waiting for the right moment to strike back. They find T, who morphs into the Hive alien and attacks the agents. He takes the crystal and attempts to activate the weapon to destroy the planet. H attempts to reach into T’s true human side, just as M gets knocked into the portal. Pawny jumps in and rescues him by pulling her back and flying with his jet pack. T appears to break through briefly, just moments before M gets her hands on the super weapon and sets it to the highest power, blasting the creature into goo and destroying The Hive’s whole base.
M and H are met by O, and they all mourn the loss of T. She them promotes M to a full time agent, and makes H the probationary director of the London branch.
The two agents return home, and, now joined by Pawny, they head out in their car for another mission.