I second the KK2 nights being cursed to sleep, and now being awoken for... for... um, what reason? :P Go for it.
Or you could go the opposite direction and have them learn from some devious (and successful) plot from some ancient villain, but then you would have to come up with the reason why he or she or it didn't just smash them... Like how the Original Lions Voltron came up with the reason why Hagar didn't just destroy Voltron when she had it... (The reason was kinda shallow: She wasn't strong enough, yet the entire series thereafter tries to do just that... )
"Illogical" - Spock.
Perhaps, one could use an adaption of Rip Van Winkle, in which an entire group of friends enter a cave, party too hard, and wake up in the Future. I don't know where I read it, but it was some short story. All the guys end up smashing themselves, after realizing there's no way back. It's really depressing.
Again. "Illogical." :P
Ok. I'm going to stop randomly ragging on and on, and go back to what I was doing: Watching the Original Star Trek, Sketching Barney Propaganda posters, and re-writing lyrics of John Lennon's Imagine. :P Â Â B)
The Knights are awoken by Vladek (if he was the one who cursed them indeed) to undermine thedude's reign. But why did he leave them alive? Perhaps, he thought they might be of use...
Idea! What if Vladek cursed them and then used some magical technique to assume their powers, but he needed them alive to keep having them.