Masterpiece Robot and the ferocious Valerie Knick-knack

When Laura a.k.a. Masterpiece Robot heads into the backyard with her little sister Molly a.k.a. Sidekick her active imagination places them instead on patrol around the perimeter of a dystopian city, guarding against supervillains. Then older sister Amber a.k.a. Valerie Knick Knack throws handfuls of fallen leaves at them, unknowingly initiating a battle for the ages.