McTeague is a somewhat unintelligent man with a dentist practice in San Francisco, Polk Street, to be exact. He goes by "Mac." His best friend, Marcus brings his cousin into the shop for a teeth cleaning. McTeague cannot resist his attraction to Trina, but Marcus sees how deeply McTeague longs for Trina, so he abandons his own romantic hopes with his cousin, and Mac wins the girl over. Trina kisses McTeague and discovers that her lottery ticket has won $5,000.
Trina's mother, Mrs. Sieppe breaks the news of the couple's engagement to be married during a party. Marcus doesn't celebrate, though, perhaps still jealous for Trina. He is definitely jealous of Mac's new $5,000 lottery ticket. After the wedding, Trina's family moves away from the Bay. Trina is somewhat neurotic, and she won't let Mac spend the money. Instead she leaves it with her uncle to invest the money. She supplements the households meager income by carving Noah's Ark with animals, which she sells through her uncle's shop. Overall, the marriage is pleasant, but stressed.
Marcus has not forgiven the couple. Marcus and Mac, best friends, are driven on multiple occasions to actual violence, but McTeague's strength is too much for Marcus. McTeague leaves him with a broken arm on one occasion. Marcus admits defeat and moves south to make a life in the country.
It seems Marcus found his revenge though, because Mac loses his dental practice. Marcus simply told the authorities that Mac was practicing dentistry without a license or degree of any kind. Trina and McTeague lose their main income and find themselves living on the wrong side of the railroad tracks, so to speak. McTeague's dark side begins to emerge, and his abusive tendencies damage the marriage. McTeague steals Trina's money from her and leaves. Trina becomes literally enamored by her investment profits.
When McTeague returns to his still-rich wife, she turns him away. He attacks her and doesn't stop until she is dead. He steals her gold (again) and makes for Mexico. Marcus joins the manhunt for Mac and catches him in Death Valley. They both fight for the money before they realize that in the middle of the Valley, they are both already doomed to die. Mac kills Marcus, but Marcus manages to handcuff himself to McTeague, leaving Mac with a dead body attached to him by the arm, with $5,000, dying in the desert.
