Michael MacKenzie is a soon-to-be senior in high school and one of the novel’s two main protagonists. He’s the star of the track team, with many friends and a girlfriend, Darcy. Michael makes the impulsive decision to shoot off his new Winchester rifle on his 17th birthday, which comes down to kill Charlie Ward and set the novel’s events in motion. Michael’s story arc traces his interpersonal struggles as he works through his guilt, denial, and grief.

At the beginning of the story, Michael makes two impulsive decisions that throw his life and relationships off course: shooting off the rifle and hooking up with Amy. Once Michael learns about his role in Charlie Ward’s death, he and his best friend, Joe Sadowski, vow never to speak about it. However, as the police investigation zeroes in on Michael, Michael begins to make increasingly difficult decisions to cover his deadly, impulsive action. These decisions result in the investigation turning toward Joe, whom Michael knows isn’t responsible, despite his few attempts to rationalize himself into thinking otherwise because of his own denial.

In addition to firing the rifle, Michael cheats on Darcy with Amy. Despite their tryst, Michael thinks poorly of Amy, referring to her as easy.