After Kirsty's mom divorces her second husband, Ian, the whole family believes the abuse will end, but Ian secures visitation rights twice a month with his daughter, Melanie, Kirsty and Tim's half-sister. Although the family has been freed of his constant physical, sexual, and verbal abuse, they now are subject to his continued emotional abuse when he drops Melanie off twice a month. He seems to find some reasonable excuse to push his way inside their house every time and really lays into them all, but he won't touch any of them, so there is no evidence. Additionally, Ian's brother is on the police force and has spread rumors that Kirsty's mom is mentally ill and an unreliable witness.
One day Kirsty invites her friend, Dylan, from school over. He's still around when Ian arrives to drop off Melanie. Concealed out of view, he witnesses the entire ordeal. Later Tim tells Dylan how their family suffers after these incidents. Kirsty has PTSD from her step dad's sexual assaults when she was younger. Tim, only thirteen at the time, drinks in secret. And their poor mom is severely unstable. Naturally Dylan wants to help, but he approaches the issue from a twisted attitude of vengeance, subconsciously hoping to avenge himself vicariously against his own abusive father who moved to England and started a new family there.
Dylan conspires with Tim to murder Ian, in their juvenile minds the only method of eliminating the threat entirely. After consulting with his grandfather through veiled metaphors, Dylan decides that he is justified to encourage Tim to do the dead. He catches a possum in his attic and tries to goad Tim into killing it in cold blood, but he doesn't succeed. Still, he and Tim steal Ian's gun and hide it in their home. When Ian discovers the weapon missing, he immediately drives over to the house. In the subsequent struggle Ian injures Tim and kills Kirsty and kills himself. By the time the police arrive, they commend Dylan, thinking he had encouraged Tim to steal the gun in order to remove the weapon from an unstable person's control. Tim spends a great deal of time in the hospital before being transferred to a psych ward. He faces no criminal charges, but his life is ruined, and his sister is dead.
