★★½

(MA) General Release

This is billed as being the conclusion in the series, and let's hope so. The first Hangover had clever plotting to make up for its sometimes obnoxious characters and a slightly cruel tone; the sequel offered more of the same, to diminished effect. But this time, the storyline is a little bit different.

Alan (the ever-irritating Zach Galifianakis) is off his medications and his behaviour is even more childish, selfish and destructive than usual. After an intervention, the rest of the Wolf Pack - Phil (Bradley Cooper), Stu (Ed Helms) and Doug (Justin Bartha), who have (somewhat inexplicably) stuck by him, are driving him to an interstate treatment centre when they are kidnapped.

Their captor is gangster Marshall (a miscast John Goodman: he seems rather too genial for this role) who has had millions of dollars in gold stolen by Leslie Chow (Ken Jeong), their depraved criminal ''friend''. He's heard Chow has escaped from prison in Thailand and figures they will be able to find and fetch him - and to make sure they do, he holds Doug hostage.

So, yes, it's a variation on the theme. Chow plays a much bigger role than previously, which is a mistake - his weird and wild antics were funny in small doses, but there's simply too much of him (in every sense), though Jeong is certainly committed in the role.

There are bright moments, including a scene where Alan - miracle of miracles - finds a woman who is attracted to him (Melissa McCarthy), and a reasonably inventive and well-staged sequence at and around Caesars Palace (which has a perhaps unintentionally funny disclaimer in the credits). But although the camaraderie is still there, it's a bit like catching up with old friends you haven't seen in a while and realising you don't have as much in common any more (and maybe never did).

And there isn't an actual hangover this time around, unless you stay until midway through the end credits: let us hope they keep their word, though, and end the series here.