In the realm of Polyphonica, ethereal beings manifest through the melodies of humanity, coexisting in a harmonious union. While these spirits remain mostly unseen, a select few wield enough power to take on human or animal guises, sharing their existence with mortals. Dantists, masters of a special music known as 'Commandia,' command reverence in this realm, often forming pacts with formidable spirits. Shinkyoku Soukai Polyphonica follows the journey of the budding Dantist, Phoron Tatara, his spirit companion Corticarte Apa Lagranges, and their companions as they navigate the intricacies of their intertwined lives and duties.