Zelda Williams stars in Lifetime movie Girl in the Box: Photos

Imagine spending nearly a decade of your life trapped in a wooden box the size of a casket. EW has an exclusive first look at the new Lifetime thriller Girl in the Box, which chronicles the life of Colleen Stan who, throughout the 1970s, did just that.

Starring the late comedian Robin Williams’ daughter, Zelda Williams, Girl in the Box revolves around a fictional version of Stan (That Awkward Moment‘s Addison Timlin), a 22-year old hitchhiker imprisoned by a young couple, Cameron (The Perks of Being a Wallflower‘s Zane Holtz) and Janice Hooker (Williams), in 1977. The pair keeps Stan in a coffin-sized box under their bed for 23 hours a day, allowing her daily reprieve from incarceration only to work as a live-in slave, babysitter, and sex object.

The TV movie marks Williams’ first major project since the premiere of Freeform’s Dead of Summer, a horror-drama from the producers of ABC’s Once Upon a Time about a group of teenage counselors at a rural camp plagued by supernatural forces. Ahead of the film’s announcement, Williams told EW she never wanted to rely on her father’s Hollywood trajectory as a means to forge a successful acting career of her own.

“Maybe out of stubbornness, but also out of independence, I never asked him for a road map – I didn’t want the curiosity to be dampened for me,” the 26-year old said. “I had to figure this out before he was gone, and now I definitely have to figure it out on my own. But I’m enjoying that process.”

A two-hour special, Colleen Stan: The Girl in the Box, revolving around real-life events which inspired the film, is set to air immediately after the Lifetime movie. The documentary features news footage and interviews detailing Stan’s first-hand account of her ordeal as she grapples with the past and attempts to forge a new life.

Girl in the Box, written and directed by Stephen Kemp, premieres Saturday, Sept. 10 at 8 p.m. ET on Lifetime. Check out an exclusive look at the film’s main cast in the character photos above and below.