In the underwater metropolis of Atlantis, where ancient technology and mythical creatures coexist, the brilliant Engineer, Aiko, a master of aquatic engineering, clashes with the enigmatic Siren, Kaito, a guardian of the city's ancient secrets. Their rivalry, fueled by contrasting philosophies of innovation and preservation, ends in a tentative alliance. As they attempt to rebuild the city's infrastructure, they encounter a series of hilarious situations, exposing the absurdity of their newfound peace. A forbidden romance between Aiko and Kaito blossoms amidst the chaos, forcing them to question their beliefs and the delicate balance of their newfound peace.