Dennis is a typical teenage boy, who lives with his sister and his two parents. He plays for the school football team and is one of the star players. He is best friends with Arnie Cunningham, the school nerd.
One day, he and Arnie are driving when Arnie sees Christine. Despite Dennis’s objections due to Christine’s extremely poor conditions and his distrust of Christine’s owner, George LeBay, Arnie buys Christine. He later witnesses Arnie fight his parents, which makes him feel uncomfortable and awkward.
Dennis soon notices Arnie changing in appearance as well as his personality. Alongside that, Dennis starts to grow afraid of Christine.
At a football game, Dennis severely injures himself and spends a while in hospital in plaster. During his stay, Dennis grows afraid of Arnie, noticing Arnie is becoming rather sinister.
Upon release, he and Leigh Cabot team up and destroy Christine in a showdown that results in Arnie’s death and the complete destruction of Christine.
In the aftermath, Dennis is indicated to have PTSD and is haunted by the memories of Christine.