When Orzhov Basilica enters the battlefield, it, Retreat to Emeria, and Kodama of the East Tree trigger.
Resolve the Kodama of the East Tree trigger, choosing not to put anything from your hand onto the battlefield.
Resolve the Orzhov Basilica trigger, returning it from the battlefield to your hand.
Resolve the Retreat to Emeria trigger, creating a token.
When the token enters the battlefield, Kodama triggers, putting Orzhov Basilica from your hand onto the battlefield.
When Orzhov Basilica enters the battlefield, it and Retreat to Emeria trigger.
Repeat from step 4.
This elegant loop turns a simple bounce land into an endless engine by weaponizing landfall triggers. As you play Orzhov Basilica, its own entry triggers alongside Retreat to Emeria and Kodama of the East Tree, setting off a cascade where the Basilica bounces itself back to your hand. Meanwhile, Retreat to Emeria provides a fresh Kor Ally token with every cycle, and that token's arrival on the battlefield satisfies Kodama of the East Tree's trigger condition to effortlessly drop the Basilica right back down.