Men in Black 1997
They are the best-kept secret in the universe. Working for a highly funded yet unofficial government agency, Kay (Tommy Lee Jones) and Jay (Will Smith) are the Men in Black, providers of immigration services and regulators of all things alien on Earth. While investigating a series of unregistered close encounters, the MIB agents uncover the deadly plot of an intergalactic terrorist who is on a mission to assassinate two ambassadors from opposing galaxies currently in residence in New York City.
 
Men in Black 2 2002
Kay (Tommy Lee Jones) and Jay (Will Smith) reunite to provide our best line of defense against a seductress who levels the toughest challenge yet to the MIBs mission statement: protecting the earth from the scum of the universe. While investigating a routine crime, Jay uncovers a plot masterminded by Serleena (Boyle), a Kylothian monster who disguises herself as a lingerie model. When Serleena takes the MIB building hostage, there is only one person Jay can turn to -- his former MIB partner.
 
Men in Black 3 2012
Even though agents J (Will Smith) and K (Tommy Lee Jones) have been protecting the Earth from alien scum for many years, J still does not know much about his gruff partner. However, J soon gets an unexpected chance to find out what makes K tick when an alien criminal called Boris the Animal (Jemaine Clement) escapes, goes back to 1969, and kills K. With the fate of the planet at stake, J goes back in time and teams up with K's younger self (Josh Brolin) to put things right.