2Activate Urban Retreat by paying and returning a tapped creature you control from the battlefield to its owner's hand, putting Urban Retreat from your hand onto the battlefield.
3When Urban Retreat enters, Springheart Nantuko triggers. Choose not to pay and create a 1/1 Insect creature token.
4Activate Earthcraft by tapping the Insect, untapping a basic land you control.
5Activate the basic land by tapping it, adding .
6Activate Oboro Breezecaller by paying and returning Urban Retreat from the battlefield to your hand, untapping Scorched Ruins.