At its best, the first Men in Black is an example of a few good ideas coming together to make an amusing trifle. The gimmick is that literally illegal aliens live amongst us and are indistinguishable from native Earthlings, who are more or less loony tunes anyway. The beauty of the Men in Black is that yes, we're watching The Ghostbusters with aliens instead of ghosts and demons, but we could well be watching an allegory which mines White America's uneasiness on immigration and the changing ethnic composition of their own country for broad comedy.

In Men in Black 3, once again Earth is in imminent danger of an alien invasion and once again, there is a city-wide dragnet for an alien. The twist this time round is it's not so much where the alien is hiding but when.

Yes, there is a time travel element in MIB3, which also ties in with a key highlight of the MIB series — the double act where Tommy Lee Jones plays the sour prune straight man and Will Smith applies his natural talent as the funny man. Since our hero goes back into the past to save the existence of the Earth (as well as that of Agent K) from a time travelling alien villain, the film has great fun casting Josh Brolin as the younger K. Half of the fun in this film is watching Brolin imitate Tommy Lee Jones better than Tommy Lee Jones can perform Agent K. The other half consists of watching the younger versions of everyone else in the MIB bureau, as well as laughing at what the bureau thought to be high technology in the 1960s.

While MIB3 doesn't really push the envelope in terms of comedy or storytelling, it does mark a return to form for the series. Plus, it's a relief to see Will Smith doing comedy again.