I described Dhoom 2 to a work colleague as The Italian Job meets Fast and the Furious but with dance numbers. It's so much better/worse than that.
The plot is very simple. Master thief defies police until know-it-all Mumbai Assistant Commissioner gets on the case and there ensues a typical cat-and-mouse chase with hot women thrown in.
What most people object to about Bollywood is the sheer ridiculousness of most movies. It's true, you can't watch a typical Bolly film without a sense of humour and a willingness to just go along for the ride. Questions of continuity or plausibility cannot be allowed to enter your mind. The opening sequence of Dhoom 2 has the master thief attempting to steal the crown of England from an incredibly unattractive 'Queen' (Queen Elizabeth II, not articulated) on a beat-up looking train going through the desert of Namibia. And that's not even where implausible starts. However, it is followed up by one of the best titles sequences ever full of sweaty writhing bodies in an amazing dance sequence. Who the hell cares about Lizzie's jewels after that?
The dance numbers are a problem for a lot of potential movie-goers. Let me explain; Bollywood films are not allowed to show direct physical contact such as kissing on screen. Material that may be offensive is not allowed to be shown, including sex and violence. So where in your typical western movie there would be a love scene, in Bollywood there is a song and dance number in which the leads express their love through song. In dance they can also touch each other and get right up close – but no kissing, never any kissing. Interestingly, Dhoom 2 does contain a kiss and shooting and mild violence. They were charged with indecency for the kiss but it passed the censors eventually and was included in the international release.
So Dhoom 2 is a great terrible movie you will really like provided you can overlook certain issues like believability and instead just enjoy the spectacle, the shirtless men / bikini-clad women and the shear fun of it all.