In San Francisco, retired Detective Nick Charles (William Powell) and his attractive wife, Nora (Myrna Loy), learn from police Lt. Abrams of the murder of a race jockey, but Nick refuses to get involved. Approached later by athletics commission head Maj. Jason Scully and reporter Paul Clarke (Barry Nelson), Nick still declines to investigate. When another reporter is murdered and Paul is arrested, Nick gives way to Nora's plea and, with their fox terrier Asta, sets out to solve the murders.