The phrase "based on true events" always sends a tingle down our spines. In a new trailer for horror flick "The Quiet Ones," those events supposedly take place in 1974 when a team from Oxford University tries to get photographic proof that ghosts exist.

"Mad Men" star Jared Harris plays the professor who leads a group of students in testing his hypothesis that poltergeists spring from negative human energy. But of course, the experiment takes a dark turn and creepy, frightening things start happening to the students.

"The Quiet Ones" also stars Sam Claflin, Olivia Cooke, and Erin Richards, and haunts theaters on April 11.