Brandon Sanderson just dropped a major Mistborn movie update, but fans might want to temper their excitement. Brandon Sanderson finishes Mistborn screenplay, but cautions movie is still earlyBrandon Sanderson recently confirmed he finished the first draft of the Mistborn screenplay. Beyond the Mistborn film, Sanderson also has a Stormlight Archive TV series in development with Apple TV. No official release date has been announced for the Mistborn film yet. Sanderson’s weekly update also covered upcoming author events and his collaboration with subscription box service Illumicrate for Fires of December.