Four years after the alien-seeking agents Jay and Kay (Tommy Lee Jones and Will Smith) averted an intergalactic disaster, Kay has returned to the comforts of civilian life while Jay has taken over his former partner’s role as the most annoyingly efficient employee of the unofficial government agency that regulates all things alien on Earth. While investigating a seemingly routine alien-on-alien crime, Jay uncovers a diabolical plot masterminded by Serleena (Lara Flynn Boyle), an evil monster disguised as a sexy lingerie model, and her two-headed, half-witted accomplice, Scrad/Charlie (Johnny Knoxville). When Serleena takes the entire MIB building hostage, Jay can only turn to the retired Kay, whose expertise represents the universe’s last best hope to avert ultimate destruction.