Heather Graham (They Will Kill You, Suitable Flesh) will play Doris Bither in What Happened to Doris?, based on one of the most documented supernatural cases in U.S. history.

Set in 1974 suburban Los Angeles, a single mother is violently attacked by an unseen force in her home. With no one believing her, she turns to a team of paranormal researchers.

Nick Simon (The Girl in the Photographs) directs from a script by Thomas Fenton (Saw IV). Steven Schneider (Insidious, Paranormal Activity) produces alongside German Michael Torres.

Mimi Rogers (Ginger Snaps), Morgan Peter Brown (Absentia), and Kevin Keppy (Smile) also star.

“This film is based on a true story and that truth is chilling,” said distributor GVN’s Head of Production Missy Valdez previously. “It is an honor and a challenge to bring Doris’s raw and terrifying experiences to the screen with care and dignity. So proud to be part of this film. This is an elevated horror film that blends emotional depth with real-life terror, and we believe it will deeply resonate with both genre fans and new audiences alike.”

What Happened to Doris? will make its world premiere at Fantastic Fest.