The year was AD 2140. Under the menace of no mercy posed by "Aions", the worst enemies ever, mankind's population reduced to the extreme and was literally on the brink of extinction... Encountering a strange incident, Nanagi Ryouga was sent flying from the peaceful world of 2015, and though shaken in that harsh environment, he stood up for the purpose of finding hope in his own fate and the future of mankind. Carrying a radiant sword in his hand— The curtains of the speed battle with a new perspective never seen before rises! (Source: Baka-Tsuki)

"Unfortunately, your "ability to see the Dimensionless Number" has already awakened." "In the Interstice of Δt people are born, and then died there." A fragile-looking girl, jumping from atop building, on her back, for a moment, wings could be seen -- that is, the high-school student me, Saegusa Seiichi and Numerologist (Arcanist) Usagi Setsuna first meeting. One day, when trying the rumor of urban story about Red Hat who can grant any wish, my younger sister Manaka is kidnapped. Me who is frantically searching for her, suddenly can see floating infinite numbers tinged with noise out of nowhere. Action story of abilities of Numbers, kick off! (Source: Baka-Tsuki)