 Early scripts concerned the 3 Doctors joining forces to combat  various incarnations of Evil, including zombies and the goddess  Kali, though this was modified after the poor health of  William Hartnell (qv) prevented him from playing a more active  role. Other suggestions included a role for Frazer Hines (qv)  reprising Jamie McCrimmon (which was abandoned as he had prior  commitments to _"Emmerdale Farm" (1972)_ (qv)) and a possible cameo  for Wendy Padbury (qv) as Zoe Herriot.