KOU is staying at the dorm of Seiran Academy High School to prevent himself from acting on his love for his sweet and meek stepbrother Naruki. But Naruhi follows him to Seiran! Now, Kou has to protect Naruki not only from himself, but from other students who want to have innocent Naruki for themselves. Enter Yoshino, Kou's roommate, with his brilliant plan-hypnotize Naruki into becoming someone who can defend himself. Kou reluctantly agrees, but the result blows his mind! Now, every time Naruki is aroused, he develops a split personality - seme-Naruki, who will take any chance to top anyone, but most especially Kou!