Men In Black 3 arrives in theaters a full 15 years after the original film came out, and a decade after its first sequel met with venomous disapproval. Given the amount of time that exists between films, MIB3 could easily lumber under the weight of the previous two features in the series. Instead, the film zips along rather smoothly with a new element: time travel.

Stars Will Smith and Tommy Lee Jones are back for this third installment, which finds Agent J (Smith) going back to 1969 in order to stop the assassination of Agent K (Jones) by Boris the Animal (Jemaine Clement of Flight of the Conchords). To do that, J finds himself working with a younger K (Josh Brolin).

The plot is really rather simple, but the choice for a past time period was a solid pick. The first two films feature enough designs that have a ‘60s influence to them. Throwing the film itself back to that decade actually manages to not feel all that jarring. Considering how many films with time travel feel overdone when going to the past, there’s a good balance with this film.

What makes the film work is the cast. Smith, in his first film role in four years, has aged well as an actor, and his performance as J works with that. He’s similar to the character’s portrayal in the original film, but just a bit older and wiser. Jones, meanwhile, does well in a limited role, while Clement is almost unrecognizable as Boris. But the biggest revelation is Brolin’s take on K. From his appearance to his phrasing and body language, Brolin mimics Jones perfectly. If anything, it’s easy to see Brolin becoming Jones within a few decades. It’s a spot-on casting choice.

While the plot is light, there’s a remarkable amount of heart to it, thanks mainly to Jones. The humor is also solid and plentiful, which – in a summer filled with sequels – is a welcome relief. In a summer filled with more serious works of science fiction and action, Men In Black 3 is a bit of a welcome breather. It’s not a complete farce, but it’s also not so serious that it can’t be fun.