The Avengers - Mrs Gale 1964 S03E26

Episode: Lobster Quadrille. In investigating the death of a colleague who has died in a fire Steed and Mrs. Gale find an ornately-carved chess piece in the dead man's possession. This leads them to an importation business. On the face of it the commodity is lobsters but it is the front for a gang trying to smuggle heroin into the country.