Men in Black 3 is a 2012 American 3D science fiction comedy film starring Will Smith, Tommy Lee Jones, and Josh Brolin. The film was released on May 25, 2012, ten years after its predecessor Men in Black II and fifteen years after the release of the original Men in Black. It also stars Jemaine Clement and Emma Thompson with Barry Sonnenfeld returning as director, and Steven Spielberg returning as executive producer. The film is the third installment in the Men in Black film series which is based on the The Men in Black comic book series from Malibu / Marvel Comics by Lowell Cunningham. Principal photography began in New York City on November 16, 2010

The intergalactic criminal Boris the Animal is aided in escape by his girlfriend, Lily Poison, from the LunarMax prison on Earth's moon. He is intent on going back in time and killing Agent K, who on July 16, 1969, shot off his arm and captured him. After investigating a spaceship crash in New York City, and following a skirmish in a, Boris appears, and K and J give chase. Boris reveals to K, "you are already dead, you just don't know it yet," and then disappears in an explosion. K deduces that Boris has escaped, and K regrets not having killed him. K returns to his apartment, and suddenly all traces of him disappear. Agent J, however, still remembers K, though no one else at Men in Black headquarters does.
Agent O, the new Chief deduces from J's statements that a fracture has occurred in the space-time continuum. The two realize Boris must have time-jumped to 1969 and killed K, resulting in an imminent invasion of Earth by his race, the Boglodites, due to the absence of the protective ArcNet shield around Earth, which was installed by K in 1969. Aided by electronic-shop owner Jeffrey Price (Michael Chernus), son of Boris' fellow prisoner Obadiah Price (Lanny Flaherty), who created the time-travel device, J time-jumps off the Chrysler Building to reach time-travel velocity (Jeffrey also cryptically, though excitedly, informing J that the reason he remembers K where nobody else can is because he was 'there'). With only 24 hours to stop Boris, J arrives a day before Boris kills K.

J follows a clue to Coney Island, where 29-year-old junior agent K arrests him and then questions him at MIB headquarters, while a young Agent O  and Chief X  come by. Getting no answers, K decides to place J in a large, primitive Neuralyzer. At the last second, J says to junior K to kill Boris when he sees him tomorrow, not arrest him. After stopping the primitive Neuralyzer, J tells K the truth. As a team, they follow Boris' trail to a bowling alley and then to The Factory, the studio / party space of Andy Warhol's, who is actually the undercover Agent W. The Agents meet the alien Griffin , an Arcadian who possesses the ArcNet and is able to see all possible futures. Griffin leaves before Boris arrives to snatch him. The Agents locate Griffin at Shea Stadium, where he gives them the ArcNet and instructs them to place it onto the Apollo 11 lunar rocket launch occurring in less than six hours. Boris then snatches Griffin, but the agents, on monocycles, give chase and recover Griffin.
Upon arriving at Cape Canaveral, the agents and Griffin are arrested by military police. The Colonel  in command, however, allows the agents to carry on their mission after Griffin uses his precognitive power to show him what J and K will accomplish. J uses the time-jump device to confuse future Boris- allowing Boris to shoot him before jumping back in time so that he can attack Boris again while avoiding the alien's attacks-, and pushes him off the pad. K, battling the current Boris, shoots Boris' left arm, causing him to fall back to the ground. K plants the ArcNet on the rocket, and the protective shield deploys after leaving Earth's atmosphere, the launch sequence destroying the future Boris. The Colonel congratulates K, who invites him to join the agency.
As J watches from the distance, however, 1969 Boris emerges from the blast chamber and fires at K. The Colonel intercepts and saves K's life but is killed by the attack in the process, just as K shoots and kills 1969 Boris. A child named James exits a military vehicle looking for his father. He pulls out a pocket watch, revealed earlier to have been passed down to Agent J by his father, and J realizes that the colonel killed by Boris was actually his father. K neuralyzes young James, telling him his father was a hero, thus fulfilling the 'prediction' that J would be present at the moment history changed.
J returns to the present day, where he meets his partner at the usual diner. There, he shows K his father's pocket watch. The senior agent, in return, tells him it was an honor to have met him that fateful day. As they leave the diner, Griffin, a few seats away, muses all is well with the world (breaking the fourth wall in the process and revealing to the audience that his powers of observation also make him aware of the real world moviegoers), except for the fact that K forgot to leave a tip, indicating they are in a timeline where the Earth is about to be hit by an asteroid. Then, K returns to the diner and leaves a tip, revealing this timeline to be one where the asteroid disintegrates when hitting a satellite, and the film ends