As a child, Haruka met a boy in a dream. The chained boy, Dean, entrusts Haruka with the "key" and screams "Never come back!". Then time passed... Haruka, who became a high school student, was dreaming of a dream she had never seen. Along with that, something that came to my right hand. While practicing the basketball club, Haruka was returning to the world of his dream at the moment when the sign became painful and he lost consciousness. Far from desperately looking for Dean, it was a mysterious man who sought a "key". And the shocking truth he told !  Note: Cover image to volume 2 is unavailable.