The Big Store was an unproduced story for season 4 of Doctor Who, co-written by David Ellis and Malcolm Hulke.
Synopsis
The TARDIS lands in a department store in 1973 London. The store has been taken over by two species of aliens — one, a master race, is identified only by numbers, while the members of the faceless slave race are named with letters. The latter are being transformed into duplicates of the humans which have been abducted onto the aliens' spacecraft to maintain the charade at the store, while the unprocessed members pose as mannequins. The master aliens intend to colonise the Earth, subjugating humanity by releasing a new strain of bubonic plague. The Second Doctor convinces the aliens to leave the Earth in peace.
Story notes
Ellis and Hulke were writing The Big Store by the autumn of 1966, and turned in the storyline for episode one on 15 November. Producer Innes Lloyd and story editor Gerry Davis liked the ideas, but felt they would work more effectively in an airport setting; Lloyd also desired a six-part serial. The Big Store was therefore abandoned, and Ellis and Hulke reworked the concept into The Faceless Ones. (REF: DWMSE 4, Doctor Who The Handbook: The Second Doctor)