It all started when he was standing on the balcony of his apartment. There he sees a young girl mauling his friend. He was filled with horrer as she twisted Jocke's head to a different direction.
After seeing his friend die, Gosta went to a state of mental instability, looking like a psychotic maniac to his friends. And because of what he saw he forbids himself to talk about it.
His friend Lacke tries to find that girl but he's too scared to talk. Scared of talking to the police and being in a dark prison room and being accused. So he leaves Lacke to find the girl alone.