It is a year since Taiki Kudō's adventure in the Digital World as he forms the “Xros Heart” basketball team together with Yū Amano, who became his junior at his school, and Tagiru Akashi. However, on his way home from game, Taiki sees a monstrous shadow within a space fluctuation before being confronted by three children. The leader of the trio recognizes Taiki and his potential but tells him not to meddle in their affairs before leaving. The next day after school, Tagiru hears a voice begging to be saved, and after seeing a spacial distortion, Tagiru gets dragged right into it and ends up in…