Inner Demon follows a film crew as they document teenage drug addict Carson Morris (Lara Vosburgh) under the guise of an educational program. In reality, the crew are filming a reality rehab show and have planned an intervention. Carson agrees to the terms and enters rehab but warns that she is possessed and that drugs are the only thing that will keep the demon at bay. With no drugs to suppress that malevolent force, she and everyone around her will find themselves in mortal danger from an entity far worse than they could have ever imagined…