College student Kou, a sexually uninhibited sub, feels the strong gaze of an unknown person while playing - the “eyes of the beast” unique to Doms who makes the subs kneel and be dominated. Since then, Kou has not been able to forget those eyes. Mitsuru, Kou's younger childhood friend, has always had feelings for Kou, even though he knows subs are not compatible with normal people. When Kou chooses to work part-time for a clinical trial for inhibitors to earn money for university tuition and decides to find a Dom who will live with him for two months, Mitsuru finds out about this and stops him, his eyes the same those unforgettable "beast eyes"...!