Board Thread:News and Events/@comment-26005122-20170401065450/@comment-26005122-20170406071827

You get one week to finish a card. After that, a new villain version starts. So if you want to complete the event, and earn the silver pin, you need to finish each card version within the week. I'm pretty certain, that each version will become harder to complete, because the health bars will most likely be higher.