Serenity is a 2005 space western film written and directed by Joss Whedon. It follows on from the canceled Fox science fiction television series Firefly, taking place about two months after the events of the final episode. Set 510 years in the future, Serenity is the story of the captain and crew of a transport and cargo ship. The captain and first mate are veterans of the Unification War, having fought on the losing side. Their lives of petty crime are interrupted by a psychic passenger who harbors a dangerous secret.

The film was released in North America on September 30, 2005 by Universal Pictures. It received generally positive reviews and opened at number two, taking in $10.1 million its first weekend, spending two weeks in the top ten, and totaling a domestic box office gross of $25.5 million and a foreign box office gross of $13.3 million. Serenity won film of the year awards from Film 2005 and FilmFocus. It also won IGN Film's Best Sci-Fi, Best Story and Best Trailer awards and was runner up for the Overall Best Movie. It also won the Nebula Award for Best Script for 2005, the 7th annual 'User Tomato Awards' for best Sci-Fi movie of 2005 at Rotten Tomatoes, the 2006 viewers choice Spacey Award for favorite movie, the 2006 Hugo Award for Best Dramatic Presentation, Long Form and the 2006 Prometheus Special Award.

Among fans, the film is commonly referred to as the "Big Damn Movie" (or "BDM"), a reference to a line from a Firefly episode in which Mal and Zoe call themselves "big damn heroes" after rescuing River and Simon "just in the nick of time". Serenity is a rare occurrence in the industry: a short-lived TV show continued as a major motion picture.

The crew of the Serenity is getting desperate. They have lain lower and lower to protect their doctor, Simon Tam, and his telepathic traumatized little sister, River, from the alliance, whom he rescued her from a year earlier. This has made getting jobs harder and now they are desperate. When they take River on a robbery during which Reavers (humans who have gone crazy and turned into cannibals) attack, Simon decides that its time to leave the crew of the Serenity for his and River's safety. She then mutters "Miranda" and goes berserk and nearly shoots Capt. Malcolm Reynolds, until her brother says the safety word to put her to sleep. Reynolds decides to take them back on board for safety, only now an alliance operative is on their tracks and making Reynolds determined to find out what "Miranda" is and what the Alliance is hiding. Written by Ubernoob

River Tam and her brother Simon are hiding out from the totalitarian government that experimented with River's brain aboard the space-freighter Serenity. Captained by a down on his luck, no faith soldier, the crew of Serenity must take jobs (legal or not) while avoiding the Alliance, and keeping the Tams safe. But when things get out of hand with the true extent of River's powers, the Alliance sends a new Operative to make sure what River knows doesn't get out. How will the crew of Serenity deal with this new threat? And what exactly does River know that the Operative is willing to kill for? Written by Michael Gettings

The crew of Serenity will take any job, even if that job isn't exactly legal. Captain Malcolm Reynolds and his crew take small smuggling and robbery jobs to keep their ship afloat, and to stay under the radar of The Alliance, the galactic conglomerate that not only rules the galaxy, but was on the opposite side of the war Mal lost years ago. But when a Simon and his unstable, telepathic sister, River join the crew, they get in much more trouble than they bargained for. A mysterious man is after River, because she stumbled onto a secret no one was supposed to know... and the alliance will do anything to get her back. Written by Alex W

Serenity follows the crew of the ship Serenity as it tries to evade an alliance assassin sent to recapture the telepath River, whose brother rescued her from an alliance facility. The crew must discover the mystery of the planet Miranda while avoiding alliance and reever ships. Eventually the crew must defend the entrance to a galaxy-wide broadcasting station while the captain, Mal, tries to tell the worlds the truth behind the mysterious deaths on planet Miranda. Written by FMJ_Joker

In the future, mankind consumed planet Earth, called "Earth-that-was", and moved to other planets and satellites. A new order is established with the totalitarian government of the Alliance, which fights and wins a war against their opponents, the independents. When Dr. Simon rescues his teenager telepathic sister River Tam from the claws of the Alliance, they are sheltered by a group of mercenaries and smugglers in the spacecraft Serenity, leaded by the former war hero Captain Malcolm 'Mal' Reynolds. The Alliance send an assassin to bring River Tam back, while Mal and his crew find out how powerful she is and the truth about the hidden planet Miranda and the origin of the cannibals Reavers. Written by Claudio Carvalho, Rio de Janeiro, Brazil

Follow up to the series "Firefly" as Mal Reynolds and the rest of the crew of the Firefly-class cargo spaceship Serenity continuing their mischief adventures while being pursued by a relentless government agent out to capture the psychic River Tam who holds a clue to her special abilities. Written by Anonymous