After FOX cancelled the low rated sci-fi series, 'Firefly,' it was clear that its passionate and vocal fanbase was not going to be satisfied until it got a proper ending. That's where 'Serenity' comes in. The film is an exciting space western written and directed by Joss Whedon. The story follows a group of six space rebels whose smuggling operations are interrupted when an assassin begins to hunt down a telepathic young girl they have on board. With plenty of sci-fi action and Whedon's trademark wit, the flick is a wild space adventure unlike anything you've ever seen. The film stars Castle's Nathan Fillion as well as Gina Torres, Summer Glau, and Alan Tudyk.