Requires

Moritte of the Frost must be in hand, or in the command zone. Staff of Eden, Vault's Key must be on the battlefield. Marit Lage's Slumber must be on the battlefield. Mana needed: plus enough mana to pay for commander tax, if applicable

Steps

1. Cast Moritte of the Frost from your hand or from the command zone by paying plus commander tax, if applicable, choosing to have it enter the battlefield as a copy of Staff of Eden.
2. Put Moritte of the Frost into your graveyard due to the legend rule.
3. Morrite of the Frost's enters-the-battlefield ability and Marit Lage's Slumber's first ability trigger.
4. Resolve the Marit Lage Slumber trigger, causing you to scry 1.
5. Resolve the Moritte of the Frost trigger, returning Moritte of the Frost from your graveyard to the battlefield as a copy of Staff of Eden.
6. Repeat from step 2.

Results