It's been 15 years since Agent K (Jones) hired Agent J (Smith), and as of late, their partnership has become...strained. The two go about their work on thin ice, with J insistently trying to crack his partner's bulletproof emotional shell as a new MIB chief (Agent O, Emma Thompson) takes over, and a grotesque, one-armed alien criminal named Boris (Jemaine Clement) appear to be stirring up some bad memories in K. Just as their partnership is on the verge of collapse, K disappears, the retroactive victim of a murder by a time-traveling Boris back in 1969. In order to save his partner's life, J jumps back to the same time period, where he finds himself teamed with the 29-year-old version of his old friend (Josh Brolin).

In some respects, the "strained" working relationship between J and K is actually an invention of the sequels; the original film doesn't pit one against the other as much as make Jones the veteran and Smith the naive rookie. Here, the Jones sequences are almost a drag; the actor, who seemed fully on-board in the original and reasonably engaged in the much-maligned Men in Black II, is on complete autopilot here, hardly moving a facial muscle or exhibiting any effort in his reduced screen time. Frankly, between the pancake makeup applied to hide Jones' advancing age and his stiff-as-a-board performance, he practically seems like a special effect.

Luckily, the film only spends about 10 or 15 minutes with Jones before jumping back to 1969, where Brolin completely invigorates the movie with a decent impression (not as uncanny as carefully selected trailer footage would have you believe, but totally pleasing), and more importantly, a surprisingly touching chemistry. Once the two characters are on the same page, Brolin and Smith easily recreate the friendly banter that made the first movie so pleasurable; at a moment late in the movie, Brolin says two short sentences to Smith that are both as affecting as any of the speeches Jones delivers in the original while being entirely indebted to that performance.

In the supporting cast, Michael Stuhlbarg is the standout, playing a neurotic alien with key information and technology for the Men in Black, and Sonnenfeld also provides the film with some pleasurable sci-fi nonsense, including a bit about chocolate milk and a truly dazzling vision of time travel that's funny, inventive, and looks spectacular in 3D (in fact, the whole film looks pretty good despite being a post-convert thanks to extensive computer graphics work). The one place the film really suffers is in the joke department: the first fifteen minutes are frighteningly laugh-free, and even when the film recovers, it does so more with heart and spectacle rather than jokes. After all the doomsaying disaster reports about the production and so many plot-heavy blockbuster sequels, it's refreshing to see a light, fun film that cares about its characters, but it's a fittingly wistful experience: Men in Black 3 feels like a film arriving on its expiration date, succeeding by reflecting on the past, rather than moving forward.