Cast Through Time | Venser, Shaper Savant | Sanctum of Eternity

(and one other card)

({8} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) ({U} magic symbol) available each turn.

Cast
Walk the Aeons by paying ({4} magic symbol) ({U} magic symbol) ({U} magic symbol) , granting you an extra turn after this one and exiling it due to rebound.
At the beginning of your next upkeep, rebound triggers, causing you to cast the exiled spell without paying its mana cost.
Activate
Sanctum of Eternity by tapping it and paying ({2} magic symbol) , returning
Venser from the battlefield to your hand.
Cast
Venser by paying ({2} magic symbol) ({U} magic symbol) ({U} magic symbol) .
When
Venser enters the battlefield, they trigger, returning the extra turn spell to your hand.
Repeat each turn.