Recently returned home from vacation, private detective Nick Charles (William Powell) and his socialite wife, Nora (Myrna Loy), are back on the case when Nora's cousin, Selma (Elissa Landi), reports her husband Robert (Alan Marshal) missing. As the duo search for the disreputable Robert, Selma's friend David Graham (James Stewart), who secretly pines for her, aids the investigation. When the three begin to unravel Robert's secret life, the missing persons case turns into one of murder.