It’s 1939. The set of the soon-to-be-classic film The Wizard of Oz is alive with tension. The demanding director has an explosive temper that threatens to erupt anytime something goes wrong. The teenage star has a hauntingly beautiful voice, but her youth and naivete keep causing delays on an already pricey production.

In the midst of it all, aging starlet Billie Burke—wearing her ephemeral “Glinda the Good Witch” gown—watches everything unfold, hoping this movie will rejuvenate her sagging career… and perhaps help her hide a few secrets of her own.