The missiles were a distraction from Shaw’s true plan.
Erik and Charles stopped one nuclear war, but the humans were determined to start another one.
Uther’s crusade against magic in Camelot sparks a shift in the balance of magic in the world.
After Nimueh wreaks her revenge on Camelot, the rest of the world is left plagued with monsters. Merlin and the few survivors from Camelot attempt to survive in a world where there is little food and few but sorcerers can walk through the earth unmolested.
After Santa Barbara is destroyed, Shawn and Lassiter try to find a safe place.
Jack ensures that there will always be pirates in the world.
Spike and Xander met up after the apocalypse.