With Christmas and its preparation over, and with nothin' but reruns on the tube, it's time to plow through the Netflix disks. This is—OK—probably a cold-blooded attempt to squeeze out another few dollars out of a beloved movie, but it's (at least) watchable.
The villain here, intent on (what else) the destruction of Earth, is "Boris the Animal", played by an unrecognizable Jemaine Clement. (Really unrecognizable: I've seen every episode of Flight of the Conchords and I didn't realize it was him until the credits rolled.) Boris escapes from the lunar prison where Agent K (Tommy Lee Jones) placed him back in 1969, and comes up with a devious plot to undo that history via time travel. Suddenly Agent K is gone in the "present"; only Agent J (Will Smith) remembers him. And the protection K wangled back in 1969 is absent, leaving Earth in peril from Boris's species. So J must travel back in time to untangle the time stream.
And so he does (spoiler, sorry). But it's an awful lot of fun along the way. J meets up with the younger K (Josh Brolin does an uncanny Tommy Lee Jones impression) and navigates the late sixties with aplomb.