Holding priority, cast Naru Meha by paying its mana cost.
When Naru Meha enters, it triggers, copying Return to Action, with the copy targeting Naru Meha.
Resolve the copy of Return to Action.
Holding priority, activate Umbral Collar Zealot by sacrificing Naru Meha.
When Naru Meha dies, it triggers, returning it from your graveyard to the battlefield.
Repeat from step 3.
Resolve all Umbral Collar Zealot abilities from step 5.
This intricate loop turns Naru Meha, Master Wizard into a self-sustaining engine by utilizing Return to Action's delayed trigger to constantly resurrect her every time she hits the graveyard. While Naru Meha copies the spell on entry to endlessly perpetuate the cycle, Umbral Collar Zealot serves as the sacrificial altar that safely dumps her into the graveyard while letting you surveil through your entire deck along the way.