Read ahead (Choose a chapter and start with that many lore counters. Add one after your draw step. Skipped chapters don't trigger. Sacrifice after III.) I — You may sacrifice a creature. If you do, each opponent discards a card. II — Return target creature card from your graveyard to your hand. III — Target opponent may sacrifice a nonland, nontoken permanent of their choice. If they don't, they lose 2 life and you draw a card.
Orzhov Basilica enters tapped. When Orzhov Basilica enters, return a land you control to its owner's hand. {T}: Add {W}{B}.
This land enters tapped. When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.) {T}: Add {W} or {B}.
Lifelink {1}, Sacrifice Alseid of Life's Bounty: Target creature or enchantment you control gains protection from the color of your choice until end of turn.
({T}: Add {W}.)
This land enters tapped. When this land enters, scry 1. (Look at the top card of your library. You may put that card on the bottom.) {T}: Add {G} or {W}.
({T}: Add {G}.)
(As this Saga enters and after your draw step, add a lore counter. Sacrifice after III.) I, II — For each player, exile up to one target non-Saga, nonland permanent that player controls until Battle at the Helvault leaves the battlefield. III — Create Avacyn, a legendary 8/8 white Angel creature token with flying, vigilance, and indestructible.