Ignatius (Daniel Radcliffe Daniel Radcliffe) and Merlin Williams (Juno Temple Juno Temple) are boyfriends and girlfriends who grew up together, but one day a year ago, their lives changed dramatically. Merlin was brutally murdered when the two were dating in the forest. After that, Iger was investigated by the police as a suspect, but he was eventually acquitted. Ignatius, who regained her freedom, could not forget Meilin for a long time, and the condemnation and questioning around her made her even more miserable. On the night of mourning for Merlin, Igor became angry and made a blasphemous act. Early the next morning, he was surprised to find that he had a pair of devil's horns, and it seemed that those who approached him would behave strangely, and would peek into each other's inner world when they came into contact with each other. The vexed Ignatius discovered the secret behind Merlin's murder and the real killer.