In the 1980s, a young guitarist called Euronymous forms a black metal band called Mayhem, the first of the genre in their country of Norway, with Necrobutcher, Manheim and Maniac on bass, drums and vocals. Quickly during the band’s uprising, Maniac and Manheim depart and are soon replaced by new drummer Hellhammer and a new vocalist from Sweden called Dead, who exhibits self-destructive behavior, which he portrays during their live shows by cutting himself and bleeding on the audience, and throwing pig heads at the posers. At a show filmed by their friend Metalion, the band meets a fan named Varg Vikernes, whom Euronymous initially looks down on.
While home alone, Dead uses his personal knife to cut his arms and throat, and then uses Euronymous’ shotgun to shoot himself in the forehead, leaving behind a suicide note. Euronymous returns home and finds the body but instead of calling the police, he takes photos of the body and moves the knife and shotgun around. After Dead’s body is taken away, Euronymous collects skull pieces to make necklaces; this disgusts Necrobutcher, prompting him to leave the band.
Euronymous soon after opens a record shop which becomes a social hub for Black Metalers like Varg, Metalion, Fenriz of Darkthrone and Faust of Emperor. After being mocked by an ego-driven Euronymous, Varg uses his anti-Christian beliefs as motivation to burn down a local church. When approached by Varg concerning his status as the leader of the Black Circle, Euronymous burns down a church with Faust and Varg accompanying.
Euronymous recruits Varg as the new bassist, a guitarist called Blackthorn and a Hungarian vocalist, Attila Csihar, for the studio session recordings of Mayhem’s first LP called De Mysteriis Dom Sathanas, and a power dispute between Varg and Euronymous arises.
After a wave of church burnings commence, Faust brutally kills a gay man, leading police to link Black Metalers to the crimes. Helvete is raided and shut down by the police, and Varg is arrested as prime suspect because of an interview with a Bergen newspaper claiming to have been the one who burned all the churches and killed the gay man. He is soon released due to no concrete evidence being placed.
In anger, Euronymous starts making death threats about Varg, who travels to Oslo in the early morning of August 10, to confront Euronymous. The two engage in a knife duel, which ends with Varg brutally stabbing and killing Euronymous. The next day, the news of Euronymous’ murder spreads fast through Norway and Varg is soon arrested. He is sent to prison for a maximum of 21 years, guilty of both the murder of Euronymous and the burning of the Fantoft Stave Church.