Living just outside the prosperous Yatter Kingdom, Leopard resides with her mother and guardians - Dorothy, Voltkatze, and Elephantus. It's been generations since the original Yatterman series, and whilst her life is far from affluent, she's content in her circumstances, unaware of her ancestral ties to the infamous Doronbow Gang. All that changes when, while exploring her home, she discovers a sealed off area adorned with a mural of her ancestors - Doronjo, Boyacky, and Tonzura. Shocked by the revelation, Leopard learns that her guardians are descendants of the notorious gangsters, and they've been banned from entering the hero Yatterman's Kingdom. Initially adamant to avoid following in her ancestors' footsteps, Leopard promises to remain on the straight and narrow. However, unforeseen circumstances may force her to break her word as she transforms into a villain in the pursuit of true justice.