In Serenity, Summer Glau plays River Tam, a 17-year old psychic genius. She and her brother are taken in by the crew of Serenity after he rescues her from an Alliance Academy where she was subjected to medical experimentation and brainwashing. The Alliance's pursuit of River acts as the film's motive.
Plot summary: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 (Natahn 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 (Sean Maher) and sister (Summer Glau), are fugitives, wanted by the Interplanetary Alliance with a hefty reward on their heads.
Summer Glau did the stunts herself with her incredible flexibility and with her background as a dancer she was able to do a lot more complex scenes than that one could expect from an actress. Watch the video of her martial art training, taken from the Blu-ray extras.
In the R. Tam Sessions that was leaked to the Internet to promote the movie Serenity. Summer Glau reprises her role as River Tam while creator Joss Whedon plays the interviewer. See River Tam Sessions for the story behind the making.