In this third film in the Thin Man series based on characters created by mystery writer Dashiell Hammett, retired detective Nick Charles (William Powell) and his wife, Nora (Myrna Loy), accept an invitation to visit family friend Col. Burr MacFay (C. Aubrey Smith) at his Long Island, N.Y., estate. Soon after arriving with their new son, Nick Jr., and family dog Asta in tow, MacFay is murdered, and the Charles family must unravel a mystery that may implicate the most unlikely of suspects.