Serenity is based on Joss Whedon's television show "Firefly," in which
interplanetary travel has brought about colonization of the planets, leading to
a combination of sci-fi and Western tropes. The film picks up where the
short-lived series left off, following the exploits of a crew of small-time
criminals and outcasts who eke out a living on the edge of space, performing
illegal smuggles and transports aboard a Firefly class cargo ship named
Serenity. Led by a quick-witted veteran from the losing side of an
interstellar war, Captain "Mal" Reynolds (Nathan Fillion), the crew is comprised
of a rag-tag assortment of characters who, despite having their differences, are
mostly loyal to one another, the closest thing that many of them have to a
family. The stability of the crew is challenged, however, by the revelation that
two of the passengers aboard, a brother and sister, are fugitives, wanted by the
Interplanetary Alliance with a hefty reward on their heads. The young woman,
River (Summer Glau), who was held captive in a government facility, has since
developed unimaginable combat skills and telepathic abilities. She appears to
have been altered by some form of experimental technology, leaving her
emotionally unstable and incalculably valuable. The ship therefore remains on
the outskirts of space, keeping it under the radar of the Alliance but placing
the crew in danger of being sacked by Reavers -- savage men who traverse the
edge of space, turning hapless goers by into food and clothing. They cannot run
forever and now, the crew of Serenity must risk everything and rely on
each other to keep River out of government hands and their ship in one piece.
One question, however, haunts the crew throughout their ordeal: is River herself
more of a threat to them than any of the enemies that pursue them? Serenity
mixes action with humor and relies on the cast's strong chemistry as portrayed
through the characters' steady rapport. ~ Cammila Albertson, All Movie
Guide