The resources of Earth have been depleted, and humanity has moved to another star system and terraformed many of the planets. All the planets are controlled by the supposedly peace-loving yet still rather authoritarian Alliance. But a frontier justice still holds sway farther from the "core planets", where outlaws like the crew of Serenity can scrape out a living if they keep clear of Alliance forces and the Reavers, savage and cannibalistic humans who dwell beyond the outer planets and raid the Alliance worlds around the rim.

In order to earn her continued passage onboard Serenity, a fugitive from the Alliance, the telepathic River Tam (Summer Glau), accompanies Captain Malcolm Reynolds (Nathan Fillion), Jayne (Adam Baldwin), and Zoë (Gina Torres) on a mission to steal the payroll of an outer planet security company financed by the Alliance. During the robbery, the crew narrowly avoids capture by a Reaver raiding party when River is able to telepathically sense their approach. Wash (Alan Tudyk), the ship's pilot (and Zoë's husband) brings the ship to intercept the crew's surface vehicle, saving the crew from a grisly fate.

River's brother Simon (Sean Maher), the crew's doctor, angrily reacts to the captain's willingness to put his younger sister in such grave danger. Captain Reynolds responds by suggesting they leave at the next planet they land on, Beaumonde, where the crew expects to sell their loot. Simon agrees to the arrangement. The Tams do indeed disembark at Beaumonde, but while the captain haggles with the buyers, River suddenly starts attacking people in the same bar that the captain and Jayne are patronizing. Despite being a 90 pound (41 kg) girl, she manages to incapacitate everyone, including Jayne, and is about to shoot Captain Reynolds when Simon arrives and shouts a phrase in Russian, causing her to fall asleep.

Simon explains to the captain that, during her captivity by the Alliance, she was trained and conditioned to become an assassin. The only thing that can stop her after this conditioning has been triggered is the "safe-word" he uttered. Despite knowledge of this new danger and his anger at not being told about the possibility of carrying a potential living weapon, the captain allows Simon and River to continue travelling on Serenity.

The crew contacts Mr. Universe (David Krumholtz), a reclusive techno-geek who dwells with his robotic wife on a planet surrounded by an opaque ion cloud. After watching the security camera footage of the bar on Beaumonde, Mr. Universe discovers that River's outburst was triggered by a subliminal message in a seemingly harmless cartoon advertisement that had been broadcast all over the Alliance during the previous weeks. He tells the crew that before her attack, River had whispered the name "Miranda." He also notes that the footage has been viewed by someone else with high Alliance clearance.

Fearing Alliance pursuit, the crew takes refuge in the Haven mining colony with Shepherd Book (Ron Glass), a priest who once travelled with Serenity's crew. Book warns Mal that the Alliance agent pursuing River is likely to be an "Operative," and very dangerous. Shortly thereafter, the captain receives a call from Inara (Morena Baccarin), another former passenger. Their conversation is awkward but pleasant enough — with no arguing — leading Mal and Zoe to the conclusion that it's a trap, but they decide to visit Inara anyway. Mal's fears are realized; Inara is held hostage by a ruthless and nameless Operative (Chiwetel Ejiofor). The Operative offers to let the captain go on his way if he turns River over to him, but thanks to Inara's quick thinking, she and the captain escape the Operative and return to Serenity, which takes off undetected.

Another of River's outbursts shows the crew the meaning of "Miranda". It is the name of an outer rim planet, which had once been inhabited but was thought to be wiped out in a terraforming accident. River had subconsciously learned something mysterious about the planet when she came in telepathic contact with a member of the Alliance Parliament during her training. Travelling to Miranda to learn more would require crossing through what is now Reaver territory, which the crew members agree would be suicide, so instead Serenity returns to Haven and Shepherd Book.

On arrival, however, the crew discovers that the outpost has been ravaged by Alliance forces, and its inhabitants killed. Mal finds Book, who has shot down the attacking ship. However, he has been mortally wounded and dies in Mal's arms. Several other outposts that had harboured Serenity in the past have also been destroyed. Captain Reynolds receives a message from the Operative claiming responsibility, and promising more of the same until River is turned over.

Mal comes out and orders that Serenity be remodelled to look like a Reaver ship, which involves war painting and mutilating the hull, making a dangerous modification to the engine, arming the weaponless cargo vessel with the settlers' cannon and tying bodies of the dead settlers to the prow. Everyone protests, but Mal furiously informs them that they can either do what he says or leave the ship now.

Serenity, now painted red and looking far more menacing, leaves for Miranda. The ship moves through a whole mass of Reaver vessels, and after an agonising wait, finally reaches the other side without incident.

Upon reaching Miranda, the crew discovers a normal, terraformed planet, with an earth-like environment which is completely habitable. The strange part is that the sprawling cities that dot the planet's surface are empty. Inside the buildings and cars are badly decomposed corpses, with no apparent cause of death. There are no signs of violence or disease. It is as if the people simply died.

The crew discover a log recorded by an Alliance research and rescue team after the disaster. The log recounts what has happened: the Alliance administered the chemical substance G-23 paxilon hydrochlorate, or simply "Pax", to the populace. It was supposed to remove aggression and thus render the planet free of violence. An unfortunate side effect was that the populace had stopped working, or eating, or caring about anything. They simply gave up on life and died in their newfound non-aggressive state. However, there was a small minority of the populace (approximately a tenth of a percent, thus given the planet's original population of 30,000,000 approximately 30,000 individuals) for which the drug had the opposite effect. They became extremely aggressive and mentally unstable, mutilating their own bodies, and killing the researchers who had come to investigate. They eventually left the planet and formed into the much feared Reavers. Thus, the Alliance was actually responsible for the creation of this menace.

Everyone is sickened by this revelation, but none more so than Mal. This was exactly the sort of thing that the Browncoats had been fighting to prevent: the Alliance's belief that they can make people "better"; that everyone must conform to them, regardless of the cost or consequence. For the first time in years, Mal is moved by something greater than himself; a belief, something he thought he'd lost in the Battle of Serenity Valley.

The plan is to reveal this secret to all the worlds by using the transmitter equipment belonging to Mr. Universe. Unfortunately, the Operative has predicted this, and is already waiting at Mr. Universe's headquarters, along with an Alliance fleet. When just about to leave Reaver territory, Serenity opens fire upon a Reaver ship. The ensuing chase by all the nearby Reaver warships causes the previously lone Serenity to emerge from Reaver space flanked by a large force of deadly Reaver ships, while the Alliance fleet was waiting near the Reaver space with the intention to destroy Serenity. There is a massive battle between the Alliance fleet and the Reaver fleet, as Wash steers Serenity towards the planet with both the Alliance and the Reavers trying to destroy them as well as each other. During the attack, the Operative's ship is destroyed, but he flees the battle in an escape pod and follows the crew to the surface.

Serenity is followed by a Reaver ship, which fires an electro-magnetic pulse at them, disabling power. Wash is able to restore emergency power at the last minute and effect a crash landing. While Serenity suffers massive damage including having one of its engines torn off, it looks like the crew is out of danger. As everyone begins to relax, a Reaver harpoon suddenly smashes through the window, impaling Wash who dies instantly. Unfortunately for Wash, the cockpit was the only point that the Reaver harpooners could attack from the outside. There is no time to mourn and Mal pulls Zoë away from Wash's dead body just as another harpoon is fired into the cockpit. Fleeing Serenity to continue their assumed mission of getting the word out, the crew decides to set up a last stand in a small corridor to hold off the Reavers and give Mal the time he needs to make way to Mr. Universe and transmit the message.

Mal arrives to find Mr. Universe has been killed. However, before he died, he was able to leave a pre-recorded message with his robotic wife which informs Mal that there is a secondary transmitter in another area of the complex. Meanwhile the crew is losing ground to the Reavers and is forced to retreat when Zoë and Kaylee are injured. The Operative arrives on the planet and runs into the robotic wife, who repeats the message, informing him where the secondary transmitter is. The crew try to close the blast door, but it stops leaving a small opening. This buys them some time, but when the doctor is shot by a stray bullet, there is no one to tend to the injured. He tells them he needs his medical bag which he left in the preceding room. River leaps through the blast door, throws the medical kit back in, closes the door and is swarmed by the Reavers.

Mal reaches the second transmitter and finds that it is inconveniently located on a platform surrounded by a large drop. He is about to attempt to reach the platform when the Operative shows up. They have a stand-off, which results in Mal being quicker on the draw and shooting (but not killing) the Operative. Mal then proceeds to try and reach the transmitter, but the wounded Operative follows him. There is a fight between them with the Operative using a pressure point which is designed to completely disable his opponent — it fails, and has no effect on Mal due to nerves severed in an old war injury.

Mal does not kill the Operative, and instead disables him with a similar move and leaves him trussed up to watch the recording from Miranda. Returning to the crew, he is informed that River was trapped on the other side of the blast door with the Reavers — presumably killed. The door opens to reveal that, instead, River has killed all the Reavers. As she finishes, the Alliance troops enter, but instead of giving permission to shoot her, the Operative orders the squad to stand down.

After the crew buries the bodies of their friends Mr. Universe, Shepherd Book, and Wash on Haven, the crew patches up Serenity in a repair yard on the planet Persephone. Just as they are ready to leave, the Operative makes his own exit, promising Mal they will never encounter each other again. In the payoff to a subplot from both the series and the film, Simon and Kaylee finally make love. Zoe tells Mal that "she's tore up plenty, but she'll fly true," and Serenity heads back into outer space, with Mal in Wash's seat at the helm, and River acting as his co-pilot. The final shot shows the ship flying off triumphantly into the distance, until a random piece of metal flies from the back of the ship and hits the camera, prompting Mal's final, inquisitive line of "What was that?".

My Review:

The big screen outing for the crew of the Serenity and it begins in the past, we finally see Simon boosting River out of the max security secret lab, and we also learn that Si knows more about her condition than he let on during the series.  The Alliance still want her back though, because with her with a witchy mind reading psychotic psychic n’all she might just have learned herself a few secrets.  After the Hands of Blue failed they sent a man with a sword to get the job done.  Serenity the ship is really in need of repair, all those space battles and weekly adventures have taken their toll on the old girl and despite a somewhat expensive looking refit there’s much more work to be done.  To fund this Mal decides to do a spot of honest bank robbing, which leads to a good showdown with Si because Mal needs Riv to do a little Mystic Meggery.  The hover mule thing is new but it fits with the décor of the ship, more than that hover ambulance did anyway.  However things go seriously wrong when the Reavers (remember them?) make a surprise return appearance and Mal and co are lucky to get out of it alive, although they do get the cash and Jayne gets a harpoon through the leg for good measure.  This of course makes Simon hyper psychotic and after a quick punch up with Mal he’s thrown off the ship with his crazy sister at the next planet, which turns out to be Tokyo in space (minus Godzilla) but River goes crazier than usual and starts a bar fight with the whole bar, and she pretty much wins (you go crazy girl) which of course means she and Simon get to go back on the ship and they go to pay a visit to Old Shep, he’s really put some age on and lost a lot of hair.  After that another old friend decides to call and not say I love you, Inara is of course being held hostage and it’s a total obvious trap, one which Mal decides to spring anyway.  The fight scene with the operative is pretty interesting, a mix of MMA and Brazilian street boxing on a Bollywood set.  Inara is forced to save Mal with a blast on incense but on returning to Book they find him dying!!!  This is a mighty shocking set of affairs, one of the main cast has been killed off!  It ain’t right, it ain’t fair, now we may never know Book’s shady past and he died on a barren planet surrounded by many others who didn’t deserve to die either.  This spurs Mal on to find out what’s so important that the operative is willing to massacre so many people for.  The answer comes from River, who tells him to go to Miranda, a planet deep in Reaver territory.  Here they learn the insane truth, the Alliance created the Reavers, they tried to do a Blake’s 7 on the population but instead 90% just died of blessed out happy nothingness while the other 10% went totally crazy weird psychobilly Cannibal Holocaust on themselves and each others.  Mal swears to get the truth out to the people and let them know what really happened, to help he opens fire of the Reavers and draws them after himself in a huge armada of death straight into the waiting Alliance’s secret huge armada of death!  Serenity slips through the battle mostly undamaged but they have to make a very skiddy landing and a Reaver ship follows them down and they kill Wash!!!  Another crewmember is killed!  At this rate no one might survive to the end of the film!  The crew plan to hold the line against the dark until I run out of B5 allusions and in doing so everyone but Inara and River are seriously wounded in some way and then River seals everyone else off so that she can take on the Reavers rape/murder squad all by herself!  Mal meantime has to have a rematch with Op Boy, it’s much more Empire Strikes Back this time but no one loses a hand, although Mal gets jabbed with the pig sticker and still comes up fighting.  Oppy tries his fatal finisher but fails and Mal darn near breaks the guy’s neck, but spares him at the end, pinning him down with the old sword through the clothes technique.  He then transmits the info about the Reavers into Alliance space, just before a whole platoon of angry extras from Aliens come crashing into the fight.  Op Boy tells them to let Mal and his crew go, the damage has already been done.  Mal and co bury their dead before setting about repairing their ship (with the cash they stole at the start of the film) and Oppy comes by for one last chat, telling Mal that the Alliance may no longer consider River a threat but they might not forgive and forget him quite so easily, if ever.  Mal goes to fly the ship but River is the one who flies Serenity up from the spacedock, before Mal takes over.  The crew have been deeply wounded by their loses but Inara’s back and maybe they’ve got more adventures to have in the future…I sure hope there’s at least one more waiting to be told.  I award the movie a very blouse bursting ten out of ten.