In 1979, police apprehend Kenneth Bianchi for the murders of two University of Washington students. His arrest shocks the world of psychiatry and sparks new life into one of America’s most notorious serial killer investigations.

Ken Bianchi claims responsibility for the Hillside Strangler murders in LA. But there’s a catch — he blames the murders on his multiple personality ‘Steve’ and his cousin Angelo Buono. Investigators must determine if he’s credible or a pathological liar.

The Hillside Strangler Task Force receives a ‘magic phone call’ from Bellingham, Washington, providing a breakthrough. Prosecutors enlist world-renowned psychiatrist Dr. Martin Orne to help untangle the devastating truth behind Bianchi’s claims.