The original “Men in Black” was an inspired summer popcorn movie.

As Agent J, Will Smith was fleet of foot and mouth, and Tommy Lee Jones as Agent K had a countenance like granite and a delivery like barbed wire. They clashed and complemented each other beautifully.

The tricky visual effects didn’t overshadow the characters’ sublime chemistry.

Since then, the filmmakers haven’t achieved the same balance. “Men in Black II” was bigger, louder and more stupid; now “Men in Black 3” goes the opposite direction. As it tries for more character interaction and depth, things such as the plot, villain, love interest and conflict come up short.

Fourteen years after their first adventure, K and J are still bickering, and still at work protecting Earth from alien nasties.

One of K’s old enemies, Boris the Animal (Jemaine Clement), escapes from a prison on the moon and seeks revenge. When J reports for work, he finds that K no longer seems to exist. He must travel back in time to stop Boris from killing K, and also save the world from a fresh alien attack.

In the year 1969, J meets the younger version of K (Josh Brolin). Brolin captures Jones’ essence to such a high degree that he falls right into the old chemistry with Smith. It’s a smooth transition, and happily, the old comedy team is back.

But is that enough? Like any so-so Abbott and Costello or Laurel and Hardy movie, “Men in Black 3” doesn’t put much effort into anything outside the main characters.

For example, Emma Thompson and Alice Eve appear as the older and younger versions of a potential love interest for Jones, but nothing comes of it.

And Clement, one-half of the hugely funny “Flight of the Conchords,” isn’t quite right as Boris. His sneering threats are oddly humor free, and nothing appears to be at stake for the heroes.

Fortunately, Michael Stuhlbarg (“A Serious Man”) adds a nice touch as a sweet, blue-eyed being that can see all times and dimensions at once. His twinkly joy in watching a crucial Mets game is infectious. And director Barry Sonnenfeld employs his usual slick, silly, offbeat camerawork for a smooth, bright feel.

The men in black are back, and this movie gets out of their way.

MOVIE REVIEW 

Men in Black 3 ★★½

Starring Will Smith, Tommy Lee Jones, Josh Brolin

Written by Etan Cohen

Directed by Barry Sonnenfeld

Rated PG-13

Running time 1 hour 46 minutes