Narset's Reversal, and Return the Favor

Prerequisites

• Narset's Reversal in hand
• Return the Favor in hand
• plus enough mana to cast the additional instant or sorcery available

Steps

1. Cast any instant or sorcery by paying its mana cost
2. Holding priority, cast Return the Favor by paying plus an additional to choose its first mode, targeting the instant or sorcery cast in step 1
3. Cast Narset's Reversal by paying , copying Return the Favor targeting the spell cast in step 1 and returning the original Return the Favor to your hand
4. Cast Return the Favor by paying its mana cost, copying the copy of Return the Favor, targeting the copy of Return the Favor
5. Resolve the copy of Return the Favor, creating a copy of Return the Favor targeting the copy of Return the Favor
6. Repeat step 5

Results

• Infinite magecraft triggers