Temporal Manipulation + Seasons Past + Demonic Tutor
Temporal Manipulation
Seasons Past
Demonic Tutor
Infinite turnsLock
How it works
Cast Seasons Past by paying 4, returning Demonic Tutor, Temporal Manipulation, and any number of cards with different mana costs to your hand and putting Seasons Past on the bottom of your library.
Cast Demonic Tutor by paying 1, putting Seasons Past from your library into your hand.Cast Temporal Manipulation by paying 3, granting you an extra turn.