Apparently the original plan for the end of season 5 & the begining of season 6 was for Mac to have gone into seclusion for 30 years (instead of only six months), and the demon guy was sposed to take over Earth! Mac comes back & the world is a dark place, but he finally beats the demon with the aid of Methos & a god knows how old, wheelchair bound Dawson!
The powers that be nixed the idea because it would have been too expensive & they didnt think a dark tv show would be popular with the viewing public!
