Happy Face is based on the eponymous iHeartMedia podcast, which tells the story of Melissa Jesperson-Moore, a contributor to the Dr. Oz show, who at age 15 discovered that her father, Keith Hunter Jesperson, was the serial murderer, known as the Happy Face Killer. As an adult, Melissa changed her name, guarded her secret, and cut off all ties to her father, who is currently serving life in prison.