During the Asian financial crisis, former banker Seo Min-ki (Choi Min-sik) loses his job and assumes domestic roles as a househusband caring for his infant daughter, while his wife Choi Bo-ra (Jeon Do-yeon) thrives as a successful English language institute executive. Unfulfilled at home, Bo-ra secretly rekindles a passionate affair with her former lover, Kim Il-beom (Joo Jin-mo). As Il-beom grows increasingly possessive, Min-ki uncovers evidence of Bo-ra's ongoing infidelity. Driven by deep humiliation and emasculation, Min-ki meticulously plots a deadly act of revenge, framing Il-beom for Bo-ra's murder.