The Avengers (1961)

S4E4 Death at Bargain Prices

After an agent is murdered in the elevator of Pinter's Department Store, Steed and Emma find themselves drawn into a case involving King Kane, a wealthy magnate residing in a penthouse above the store. Meanwhile, the mystery deepens as they discover that Professor Popple, a renowned atomic scientist who has gone missing, is being held captive in the store's bargain basement.