It's 1985. Pony Darlene Fontaine has lived all her fifteen years in "the territory," a settlement founded decades ago by a charismatic cult leader. In this strange town run on a sinister economic resource, the women crimp their hair and wear shoulder pads, and the teenagers listen to Nazareth and Whitesnake on their Walkmans. Pony's family lives in the bungalow at the farthest edge of town, where the territory borders the rest of the wider world - a place none of the townspeople have ever been. Except for Billie Jean Fontaine, Pony's mother. When Billie Jean arrived in the territory seventeen years prior, falling from the open door of a stolen car, the residents took her in and made her one of their own. Beautiful, beloved, and secretive, Billie Jean has always refused to describe the world she came from. Pony adores and idolizes her mother, but like everyone in the territory she is mystified by her past. One night, Billie Jean announces that she is going into town. She grabs her truck keys, bolts barefoot into the cold October darkness, and vanishes. Billie Jean was the first person to be welcomed into the territory. Now, with a frantic search underway for her missing mother, Pony fears: Will she be the first person to leave it too?