In a world where Concept governs existence across ten alternate realms, a looming collision threatens annihilation for those lacking in this vital force. Standing on the brink of destruction, the Concept War unfolds as the world of Low-G, devoid of Positive Concepts, seizes the Concepts of other worlds to survive, leaving only itself standing. Now, six decades later, Low-G faces a new peril as its Negative Concepts surge uncontrollably. To avert demise, Low-G must now seek Positive Concepts from the remaining alternate worlds. Enter Mikoto Sayama, inheritor of a legacy tied to the Concept War and negotiations. Tasked by UCAT, the organization behind the past destruction, Mikoto steps into the negotiation seat burdened by the ominous family legacy 'The family name Sayama is villain itself' and the weight of past grievances, embarking on a journey to secure salvation for Low-G.