Genauer steht es in der FAQ:
What do your heroes keep and lose between Acts of a single Story Quest?
• Keep your Hero deck. This includes any modifications made through
completing previous Story Quests or defeated Agents.
• Keep items, Potions, gold, and Serendipity.
• Keep your earned titles.
• Keep the ongoing consequences of any completed or failed quests.
• Keep contents of the treasure bag, including any modifications made.
• Keep the Quest deck. This includes any unlocked quest chains.
• At the start of a new Act, Hero and Darkness decks are reshuffled, Hero
Vitality is reset to its maximum value, and the Darkness AP is reset to zero.