The spiritual angle in Serenity is just one of the many elements making this one of the most ambitious, one of the most challenging — and one of the most entertaining thrillers in recent years.

From its intense beginnings to its what-really-c’mon-no-reallllllly-c’mon mid-film twist to its defiantly and successfully sentimental finale, the new Matthew McConaughey vehicle is playing by its own demented rules. When it deigns to care about rules.

Though Serenity is blessed with a goofily enjoyable high concept, it doesn’t exploit it very effectively. You can make the viewers detectives themselves, allowing us to slowly unravel a mystery, or you can give up the charade early and just run with the premise you’ve opted not to conceal very carefully. There’s little sense in doing neither.

The big reveal at the end of the second act is absurd enough to pump some adrenaline into the third act, but the movie drags on too long afterwards.

The oily slick of sin across the surface of this film isn’t what makes it wickedly fun; it’s the utter devotion to its bonkers twist, at once defying logic and good taste. Serenity knows it’s trash, but that’s not to say that it’s not entertaining trash.