The critical element of this story is the opening of the Helvault, freeing Avacyn and releasing Griselbrand upon the plane of Innistrad. It's going to be a battle for the ages. In the video, the Helvault is opened through Liliana's machinations, but at your local prerelease you could have the opportunity to open your own Helvault!
For the Avacyn Restored Prerelease, stores were able to register for a limited number of Helvault Prerelease Kits along with the standard kits that come with every prerelease. When players at the special Helvault Events get achievements, they'll each physically break a seal on their store's own Helvault. Once all the seals have been broken, the store will open their Helvault and all the players will share the spoils within!
Here are a few important notes:
1. Registration in these events may be limited. For this reason you should check with your local store to see if they are taking preregistration. If they are, you can sign up early for a chance to play in this exclusive prerelease event.
2. Not every tournament at an Avacyn Restored Prerelease will feature a Helvault. Be sure you know if you're signing up for a Helvault Prerelease Event. You can play in multiple prereleases, but the Helvault events themselves may be open to a limited number of players.
You're probably wondering what's in the Helvault. Well, it's a secret. It's a secret even to the web team! The Helvaults are all sealed and won't be opened until players unlock the seals at the Avacyn Restored Prerelease!