She was one of the best villains on the show but what exactly is Saffron's backstory on Firefly? It speaks to the quality of Firefly that despite the fact it only lasted fourteen episodes it's still a beloved show. Joss Whedon (The Avengers) created the series, which is a space western following the crew of the Serenity as they take any dangerous or illegal jobs they can to survive on the edges of space.
The Serenity crew were partly inspired by the crew of the Betty from Alien: Resurrection, which Whedon penned the script for. While he hated the final movie he felt the idea of space outlaws could make for a fun show all its own. Firefly is remembered for its great cast and characters, combined with Whedon's ear for witty dialogue and a whole lot of worldbuilding. Sadly, the show was quickly canceled, though robust DVD sales led to Universal backing a movie spinoff called Serenity. The movie explored the backstory of River Tam, but while fans loved the big screen version, the film was box-office dud.
Years before her breakout role as Joan Holloway on Mad Men, Christina Hendricks guest-starred as the mysterious Saffron on Firefly. She first appeared in the episode "Our Mrs. Reynolds" where she poses as a naive girl Mal marries after a drunken celebration. It's soon revealed she's a con artist looking to hand Serenity over to pirates. Her scheme is foiled, though the crew ends up working with her on another job in "Trash." This episode also reveals she was married to another man and details of her backstory are teased out.
That said, Firefly never reveals much of her backstory. Her real name is never revealed but Inara believes she had Companion Guild training, considering her talent for seduction. She also seemed to have some genuine feelings for Durran Haymer, one of her many husbands, who still loved her even when he knew she had betrayed him. Saffron is quite skilled at lying and manipulation, however, so even the little she's revealed about herself is in question.
Saffron's backstory was explored in greater detail in Boom! Studios one-shot comic Firefly: Bad Company. Written by Josh Lee Gordon, the comic explains three different timelines. Saffron's real-name still isn't stated, though it's revealed she grew up poor and after her father died from an illness she was taken in by the local companion house. She worked as a servant there for most of her teen years, until she decided to break away and steals an expensive ring at a ritzy gala. She also seduces and then stabs a partygoer after overhearing some distasteful comments he makes about the poor.
The final pages of Firefly: Bad Company reveal a grown-up Saffron, who is being interrogated by an agent looking for information on Mal. She quickly escapes custody by knocking out her interrogator, but while the comic appears to offer more info on her backstory, it's possible everything she said about her past in the comic was a lie. Given that an element of mystery is kind of essential to Firefly's Saffron, letting readers decide for themselves if she's telling the truth or not feels like the right decision.