Five years after the events of the earlier film, Agent K (Tommy Lee Jones) has assumed civilian 
life as a small town's postmaster while Agent J (Will Smith) continues to work for the Men in Black, the self-funded New York City-based agency that secretly monitors and regulates extraterrestrials' activity on Earth. J is largely without a partner, his former partner Agent L having returned to her former task as a deputy medical examiner and her successors having been expelled from the agency by J himself. While investigating a seemingly routine crime, J uncovers a diabolical plot by Serleena, a sadistic, shapeshifting Kylothian queen who disguises herself as a lingerie model, but resembles a Lernean hydra in her own form. To circumvent her plans, J must convince K — who has no memory of his time spent with the agency, but is the only person alive who knows what is needed to defeat Serleena — to reunite with the MIB before Earth is destroyed.
A large part of the plot centers on Agent J's relationship with
a woman called Laura Vasquez (Rosario Dawson), a waitress at a SoHo pizzeria who witnesses Serleena's killing of the pizzeria's owner. Rather than erase her memory according to MIB rules, J allows her to retain it. As Laura becomes increasingly involved in the battle between Serleena and the MIB, she comes to view Agent J as her protector, while he simultaneously falls in love with her. When J tries to deneuralyze K, MIB is put into lockdown and they are ejected from the building. He then takes K to Jack Jeebs (Tony Shalhoub), who built an unofficial deneuralyzer. Although K regains his memory, he reveals that he still has no memory of the "Light of Zartha" but left himself a series of clues in case he needed to remember.
Ultimately, Laura's true identity is revealed as an extraterrestrial princess and power-source styled the "Light o
f Zartha". This revelation requires her to return to Zartha, her ancestral homeworld. Serleena, who has been seeking all along to find and possess the Light of Zartha, is killed just as Laura is transported away. Agent K is said to have had a romantic attachment to Laura's mother Laurana, after whom she is named, who was killed by Serleena twenty-five years before the film's story began; as a result, there is an implication that Agent K may be Laura's father, although this is never made explicit. When Laura has gone, K and Agent Zed (the head of MIB) attempt to console J for his loss, only to have him answer that he needs no consolation, having accepted her departure without much sorrow. Since people all over New York City have witnessed these events, an emergency neuralizer built into the Statue of Liberty is used to erase everyone's memory.
Two other plot threads relate the interaction of J with Frank the Pug (an extraterrestrial refugee posing as a pug dog, who becomes J's partner early in the film) and the revelation that K keeps a race of minuscule extraterrestrials inside a storage locker at Grand Central Terminal, the locker encasing their whole world. At the end of the film, K kicks open a forbidden door to reveal that a much larger locker located in a larger version of Grand Central Terminal contains the human world.
life as a small town's postmaster while Agent J (Will Smith) continues to work for the Men in Black, the self-funded New York City-based agency that secretly monitors and regulates extraterrestrials' activity on Earth. J is largely without a partner, his former partner Agent L having returned to her former task as a deputy medical examiner and her successors having been expelled from the agency by J himself. While investigating a seemingly routine crime, J uncovers a diabolical plot by Serleena, a sadistic, shapeshifting Kylothian queen who disguises herself as a lingerie model, but resembles a Lernean hydra in her own form. To circumvent her plans, J must convince K — who has no memory of his time spent with the agency, but is the only person alive who knows what is needed to defeat Serleena — to reunite with the MIB before Earth is destroyed.A large part of the plot centers on Agent J's relationship with
a woman called Laura Vasquez (Rosario Dawson), a waitress at a SoHo pizzeria who witnesses Serleena's killing of the pizzeria's owner. Rather than erase her memory according to MIB rules, J allows her to retain it. As Laura becomes increasingly involved in the battle between Serleena and the MIB, she comes to view Agent J as her protector, while he simultaneously falls in love with her. When J tries to deneuralyze K, MIB is put into lockdown and they are ejected from the building. He then takes K to Jack Jeebs (Tony Shalhoub), who built an unofficial deneuralyzer. Although K regains his memory, he reveals that he still has no memory of the "Light of Zartha" but left himself a series of clues in case he needed to remember.Ultimately, Laura's true identity is revealed as an extraterrestrial princess and power-source styled the "Light o
f Zartha". This revelation requires her to return to Zartha, her ancestral homeworld. Serleena, who has been seeking all along to find and possess the Light of Zartha, is killed just as Laura is transported away. Agent K is said to have had a romantic attachment to Laura's mother Laurana, after whom she is named, who was killed by Serleena twenty-five years before the film's story began; as a result, there is an implication that Agent K may be Laura's father, although this is never made explicit. When Laura has gone, K and Agent Zed (the head of MIB) attempt to console J for his loss, only to have him answer that he needs no consolation, having accepted her departure without much sorrow. Since people all over New York City have witnessed these events, an emergency neuralizer built into the Statue of Liberty is used to erase everyone's memory.Two other plot threads relate the interaction of J with Frank the Pug (an extraterrestrial refugee posing as a pug dog, who becomes J's partner early in the film) and the revelation that K keeps a race of minuscule extraterrestrials inside a storage locker at Grand Central Terminal, the locker encasing their whole world. At the end of the film, K kicks open a forbidden door to reveal that a much larger locker located in a larger version of Grand Central Terminal contains the human world.