One plot thread absent from Davies' pitch document was the running theme of the words “bad wolf” dogging the Doctor and Rose throughout the season's adventures. (This appeared in dialogue from the Moxx of Balhoon in
The End Of The World, during Gwyneth's conversation with Rose in
The Unquiet Dead, as spraypainted graffiti on the side of the TARDIS in
Aliens Of London / World War Three, as Henry van Statten's codename in
Dalek, as a TV channel in
The Long Game, scrawled on a poster in
Father's Day, in German as the name of the bomb in
The Empty Child / The Doctor Dances, and finally in Welsh as the designation of the nuclear power station in
Boom Town. The words had also crept up in various associated media, such as the spin-off novels from BBC Books and in additional footage on the BBC's
Doctor Who website.) Davies had begun developing the notion while writing
Aliens Of London. Although he was initially uncertain as to whether the “bad wolf” element would continue into a potential second season (or even be abandoned altogether), Davies eventually planned for the arc to come to fruition in the year's final adventure. Consequently, he renamed “Gameshow World!” as
Bad Wolf.