The cards that are upgraded stay with your character from scenary to scenary, or reset to all basic cards?

Thanks

They reset to basic cards for each scenario.

However, as far as I can tell, it is the quest cards that tell you when to upgrade rather than the rules. This means it would be a simple thing to release a campaign expansion with new quests that did allow you to maintain upgraded cards from scenario to scenario like you did in Warhammer Quest: The Adventure Card Game. I suspect, however, that we will see fan-made campaigns long before then.