"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)