15 years ago, a dimensional gate that no one has seen before, appeared over the Pacific ocean. Beyond the bundle of a cloud-like gate that always changes its form, lies a strange world. A world where fairies and monsters exist. The “Leto-Semani”. City of San Teresa, Caliaena island is a city located on a giant island that suddenly appeared together with the gate. Built in the northern part of the island, it became the front gate of both worlds. Tilarna Exedilica is a knight squire from another world. Kei Matoba is a detective of special force police department. They have to chase after the same culprit, in this city of the borderline between science and magic.