Marlene King

With four seasons of the teen thriller Pretty Little Liars under her belt (the fifth season debuts June 10), showrunner I. Marlene King will adapt the upcoming YA thriller The Merciless for the big screen. 

Written by Danielle Vega, the horror novel is an occult take on a standby format: protagonist Sofia Flores is grateful to be allowed into the popular girls' clique, until she learns that they're not so nice to their social inferiors. Sofia simply stood by when her new friends claimed their rebellious classmate Brooklyn was possessed. But once the neo-Heathers kidnap and begin exorcising their punky peer, Sofia feels just as trapped as the poor girl they're tormenting. 

"I've had a great time collaborating with [Alloy Entertainment President] Les Morgenstein and Alloy on Pretty Little Liars and have enjoyed the thrill of scaring millions of teenagers every week," commented King. "I intend to be merciless with the script and hope our audience will need to sleep with their lights on after seeing the movie."

[h/t Deadline]