In the diverse Gokuraku district, where humans, beastmen, and now mermaids coexist, Tao and Alma, two versatile troubleshooters, thrive on solving problems for a price. Driven by money, food, and Tao's whims, they reluctantly agree to aid the timid mermaid Nene. Their mission? To rescue Nene's sisters who, trapped in debt from purchasing costly medicine to maintain human appearances, are forced into dark compromises. Unconstrained by conventional notions of righteousness, Tao and Alma navigate this gritty realm guided solely by their desires.