In late 1969, script editor Terrance Dicks contacted new writing duo Bob Baker and Dave Martin after reading a draft script they had sent around the BBC for another production, "A Man's Life". After offering the duo a seven-part story in November 1969 for "Doctor Who"s eighth season, Baker and Martin submitted some various storylines they had. Despite the storylines not being suitable for a serial, Dicks commissioned an opening episode from them on 1 December, but as part of a six-parter, rather than a seven-parter.