The Walking Dead's Chandler Riggs and Super 8 star Joel Courtney have signed on for the Stephen King adaptation Mercy for Universal Pictures.

The story centers on two brothers (Chandler Riggs and Joel Courtney) who go with their mother (Frances O'Connor) to take care of their grandmother. The boys soon discover that their grandma is actually an evil witch who uses black magic. The project is based on Stephen King's short story Gramma, first published in 1984.

We reported last month that The Haunting in Connecticut filmmaker Peter Cornwell has signed on to direct, working from an adapted screenplay by Matt Greenberg. Jason Blum, Mary Viola, and McG producing. No production schedule was given at this time.