So at the end of the main quest, you have the option to sell your elder scroll to the college librarian, this dlc could be started when that's been done. Maybe something/someone is attacking winterhold or areas of skyrim that is linked to the great collapse.
So you travel back in time using the elder scroll and experience what actually happened, who was to blame and how to defeat this new enemy in skyrim. I'm thinking this could be linked to one of the daedric lords, maybe a weapon was lost in the great collapse that can be found by traveling back in time..
What do people think?
Also it's not like this is real physics, this is some crap the developers made up, make your own stuff up.
