John Farley, a self-help author, returns to his hometown only to discover that his widowed mother is dating his former gym teacher, Mr. Woodcock. Farley's high school memories are far from fond, largely due to Woodcock's harsh teaching methods and demeaning personality. The gym teacher, who made Farley's teenage years miserable, seems unchanged. Farley is shocked and disturbed by his mother's choice of partner, finding Mr. Woodcock's abrasive nature incompatible with his mother's gentle demeanor. This revelation sets Farley on a mission to prove that Woodcock is not the right man for his mother, hoping to save her from what he perceives to be a disastrous relationship.

As Farley embarks on his crusade, he is confronted by the unresolved issues of his past. His efforts to expose Woodcock's true nature and protect his mother lead to a series of comedic yet increasingly tense confrontations. Farley's obsession with discrediting Woodcock not only strains his relationship with his mother but also forces him to confront his own insecurities and shortcomings. The battle of wills between Farley and Woodcock becomes a reflection of Farley's struggle to come to terms with his past, challenging his beliefs about moving forward and the nature of forgiveness.