Welcome back, Mr. Smith and Mr. Jones.

The stars and director of one of the most creative and purely entertaining movies of the last 20 years are back for a third that does not match the original but makes up for the mangled sequel.  It has some references and tributes to the first two, though it is not overly bothered about consistency with the prior stories either in the details or in the tone.  This one seems balanced more toward the sci-fi action and less toward the wonderfully understated comic sensibility that made the first one so refreshing.  Nothing in this film reaches the matchless “Now I’m going to have to buy the White Album again” and testing scene moments of the first one.  But those black suits still fit and it is still a lot of fun.

High-spirited J (Will Smith) and craggy, taciturn K (Tommy Lee Jones) are agents for a super-secret government organization that handles immigration problems and aliens — not the kind from other countries, the kind from other planets.  Some are refugees, some are tourists, but some are here to wipe out all of humanity.  The Agency manages all of that and with the help of a flashing “nebulizer” the size of a pen to wipe out the memory of any human unlucky enough to experience an alien encounter.

One of the most dangerous aliens of all is Boris the Animal (“Flight of the Conchords’” Jermaine Clement), captured back in 1969 by K and now locked away in a prison on the moon.  As the movie opens, an incomparably luscious lady in a tight, tight dress and high, high stilettos (no special effects needed here: it’s Pussycat Dolls’ Nicole Scherzinger) is bringing him a very frosty cake.  As everyone but the prison guards guesses, what is in the cake makes possible Boris’ escape back to earth, where he picks up a time machine and goes back to 1969.  He plans to replay his encounter with K so that instead of losing an arm and getting captured he kills K and continues with his destruction of the planet.  And so J goes back in time, meets up with the K of 1969 (Josh Brolin, nailing it).

The expected fish-out-of water time travel jokes include technology (the pre-chip nebulizer is big and clunky!) and encounters with the people and events of the era.  One of the best jokes in the first movie was the display of monitors that revealed that people like Al Roker, Isaac Mizrahi,  director Barry Sonnenfeld, Sylvester Stallone, Dionne Warwick, Newt Gingrich, and Anthony Robbins as aliens.  In this version, it seems unimaginatively on-the-nose to include Lady Gaga, but back in 1969 there is a witty twist as one of the likeliest alien suspects of the era is revealed to be an undercover Man in Black instead.  Michael Stuhlbarg (“Hugo,” “A Serious Man”) is charming as a sweet-natured alien in a ski cap whose gift and curse is his ability to see every possible outcome.  I am sure at least a couple of those possibilities would have been better than this movie’s conclusion, which is muddled and unsatisfying.

Parents should know that this film includes extended sci-fi action violence with chases, explosions, and aliens, some disturbing images, some strong language, and brief suggestive alien sexual references.

Family discussion: How did what J learned about his own past change him?  How will K be different and why?

If you like this, try: the first “Men in Black” movie (be sure to try the DVD’s director commentary) and “Hitchhikers Guide to the Galaxy”