Color Identity: U

Initial Card State
- Extra Turn Spell in hand.
- Isochron Scepter on the battlefield.
- Narset's Reversal in exile (exiled by Isochron Scepter).
Mana Needed
- ({2} magic symbol)
plus enough mana to cast the Extra Turn Spell each turn available.
Steps
- Cast the Extra Turn Spell by paying its mana cost.
- Holding priority, activate Isochron Scepter by paying ({2} magic symbol)
and tapping it, casting a copy of Narset's Reversal. - Resolve the copy of Narset's Reversal, causing you to copy the Extra Turn Spell, and return the original Extra Turn Spell to your hand.
- Resolve the copy of the Extra Turn Spell, causing you to take at least one extra turn after this one.
- Repeat each turn.
Bracket Tag
This combo has been estimated to be Ruthless (Bracket 4+).