Men in Black 3D (PG)

Barry Sonnenfeld, 105mins. Starring: Will Smith, Josh Brolin, Tommy Lee Jones

Surprise of the week. Perhaps it's only because expectations were so low going in that this second MiB sequel felt like, at times, improbable fun. The return of Smith and Jones as Agent J and Agent K seemed destined to be a matter of duty rather than pleasure, which may be why the older partner, looking his years, spends so much time offscreen. No matter, as it happens, because this film is borrowing from Back to the Future and sending Agent J on a rescue mission.

The plot: vicious extraterrestrial crim Boris the Animal (Jemaine Clement, buried under prosthetics) has escaped a supermax prison on the moon and travelled back in time to eliminate Agent K.

So J plummets down the same "temporal fracture" to July 1969, when his future partner K is a young agent played by Josh Brolin, who does Tommy Lee Jones's laconic schtick possibly even better than the original.

The timebends allow for some cute 1960s gags about race (Smith is pulled over by cops just for being a black man in a car) and art (a visit to Warhol's Factory reveals that Andy is actually an undercover MiB sick of wearing a wig and listening to sitar music), not to mention the fun with outsize gadgets: a 1969 zap gun looks like Liberace's hair dryer.

Brolin's presence gives a lift to the formula and challenges Smith to raise his game; Emma Thompson crops up as an Agency head who might have been K's special one. The real disappointment is Clement, who as one of the funniest men in cinema has been given no comic leeway at all. Why did they bother hiring him? Never mind. After the calamitous MiB2, this third one looks almost classy.