Rise of Red Skull: What happens if you draw Shadows of the Past as Black Widow while fighting the Taskmaster villain in the…

Your nemesis minion cannot enter the game in this instance, so it will remain set-aside and does not enter the game. However, you still reveal your nemesis’ side scheme and shuffle the rest of the nemesis set into the encounter deck. This will cause Shadow of the Past to gain surge as dictated by the card.

-The Rise of Red Skull rulebook