So y'all will be playing as planeswalkers who have come to Sephera in search of the dragon, Nicol Bolas, who it is rumored is once more active in the multiverse (Note this takes place BEFORE War of the Spark, almost directly after the events of Shards of Alara)
You are met by the Archangel Melsyn, a fellow planeswalker who recognizes you for what you are and asks you to help her unite the various warring Courts of Sephera, so that they can stand against the dragon. To do so, you'll need to ingratiate yourself to the various courts (There are five, one for each "Wedge" in magic) and earn an audience with their leaders
You've started off with the Trokynd, an order of ascetics and druids and shamans, living in harmony with nature and venerating the cycle of life and death. Melsyn told you they would likely be the most receptive
When you arrive on Trokynd lands, their leader, Skul, informs you that the bones of Ulkesh, the Trokynd's founder, have disappeared, and before he's willing to talk to you, you must venture into the Strigand Marshes to find them, as he suspects necromancers from the Strigand court have stolen them away...

For your characters
Use the dungeon world character sheets.
I want you guys to come up with a few things in your backstories
What plane you're from (You can use existing ones or come up with your own!) and how your spark got ignited
Your spark likely got ignited by a traumatic event, although it could also be a moment of great joy