Karasu Bank’s Central Branch—a perfectly ordinary bank on the outside. One day, newbie banker Akira Mitarai is transferred to the “Special Operations Department” and led by its mysterious manager, Zenimaru Usami down into the depths hidden deep beneath the bank. There, he discovers a gambling den secretly owned and operated exclusively for high-rollers. Akira is stunned by the intense games of chance and effortless style of enigmatic gambler Shin Mafutsu, and finds himself unable to forget the thrill of going all in…!? Banker × Gambler — a new era of gambling begins!!