At 13, Simone witnesses the murder of her mother. To cure her shock, she is hypnotized in order to relive the traumatic event. We then dive into her unconsciousness at different times of her life. At 25, struggling with obsessive guilt, she confronts her mother's murderer. Then, at 60, as a renowned physicist, she gives a lecture on the strange nature of time. Endorphine is a visceral and hypnotic trip that challenges, like dreams, our perception of time and reality.