After the decline of the once robust fields of science and technology, a new energy source known as magic fuels the modern era. Humanity creates forbidden biological weapons: Gears. Those Gears eventually stand against humanity in a rebellion. Although they manage to overcome in the struggle for survival known as the Crusades, humanity's losses are so great that even after several decades pass, their emotional wounds remain unable to fully heal. Sin Kiske, the child of a human and a Gear, heads to his father Ky and mother Dizzy's wedding ceremony. Their wedding breaks the ultimate taboo: a union between a human and a Gear. Even with the world at peace, it took many years for such a ceremony to come to fruition. Despite the complex array of emotions surrounding it, the wedding ceremony is met with blessings. When suddenly, a mysterious girl appears... The fated child inheriting Gear blood-and the mysterious girl who despises Gears. Their meeting would shake the world.

En el submundo corporativo, las disputas se resuelven con sangre en peleas clandestinas. Ohma Tokita no busca dinero, solo ganar.

A pesar de que el mundo deja atrás la guerra y los avances tecnológicos traen cambios en su vida, Violet aún anhela volver a ver a su comandante.

Un día, 30.000 usuarios japoneses se ven repentinamente atrapados en un juego en línea de larga tradición. Shiroe, un estudiante de posgrado con ocho años de experiencia en juegos, también se encuentra varado en otro mundo.

Souta Takanashi trabaja en el restaurante Wagnaria con Popura Taneshima y otros colegas excéntricos, viviendo situaciones cómicas y payasadas en el trabajo.