Based on a comic book I haven't read (yes, I said comic book, not graphic novel, so there :P), it takes place in the mid '80s (when the comic was written), in an Earth with a different recent history based on the effects that such superheros can have on the World and History (Nixon in a fourth term, Vietnam war won, etc.), with a prominent appearance by that 70's-80's icon the Smilely Face. The Watchmen are a recent group of retired superheros, replacing the original Minutemen superhero group of the World War II era; things kick off with the violent murder of The Comic, one of the Minutemen who later joined the Watchmen. Thus begins the conspiracy.

This is not your normal superhero group fights big bad guy type film, but rather a whodonit more from the point of view of the heros' personal life than their public personna. Some reviews say this is a deconstruction of the superhero mythos; I've observed that if it's done for comedy then it's a parody, while if it's done for seriousness then it's a deconstruction (just an observation). Anyway, on it's own terms it's a pretty good film, involving a bit more of the intellect than the usual superhero flick. There's an IMAX version out which I managed to miss, but I can't see how a normal-screen version would detract from this film or an IMAX version improve it much. The special effects seen in the trailers are pretty much the big effects moments, the bulk of the movie being more the investigation, some flashbacks to key moments, and an ending that's not the usual clean-cut ending.

Definitely a keeper to watch, man.