When Flamehold Grappler enters the battlefield, it triggers, copying the next spell you cast this turn.
Cast Mythos of Illuna by paying its mana cost, targeting Flamehold Grappler.
Flamehold Grappler and Storm-Kiln Artist trigger.
Resolve the Storm-Kiln Artist trigger, creating a Treasure token.
Resolve the Flamehold Grappler trigger, copying Mythos of Illuna, with the copy targeting Flamehold Grappler.
Storm-Kiln Artist triggers, creating a Treasure token.
Resolve the copy of Mythos of Illuna, creating a token copy of Flamehold Grappler.
When the token Flamehold Grappler enters the battlefield, it triggers, copying the next spell you cast this turn.
Holding priority, activate two Treasures by tapping and sacrificing them, adding .
Cast Narset's Reversal by paying , targeting Mythos of Illuna
Flamehold Grappler and Storm-Kiln Artist trigger.
Resolve the Storm-Kiln Artist trigger, creating a Treasure token.
Resolve the Flamehold Grappler trigger, copying Narset's Reversal, with the copy targeting the original Narset's Reversal.
Storm-Kiln Artist triggers, creating a Treasure token.
Resolve the copy of Narset's Reversal, returning the original Narset's Reversal to your hand and creating a copy of Narset's Reversal targeting Mythos of Illuna.
Storm-Kiln Artist triggers, creating a Treasure token.
Resolve the Narset's Reversal copy, returning Mythos of Illuna to your hand and creating a copy of Mythos of Illuna targeting Flamehold Grappler.
Storm-Kiln Artist triggers, creating a Treasure token.
Resolve the Mythos of Illuna copy, creating a token copy of Flamehold Grappler.
When the token Flamehold Grappler enters the battlefield, it triggers, copying the next spell you cast.
Activate up to four Treasures by tapping and sacrificing them, adding enough mana to cast Mythos of Illuna.