Shinichi Izumi might seem like an ordinary high school boy, but he harbors a deadly secret-an alien parasite has taken him as its host. After failing to subsume him completely, the parasite was forced to settle in his right arm, and a strange partnership was born. With threats around every corner--parasite and human alike-they must learn to work together or perish. But this parasite is ruthless, deadly, and utterly indifferent to human suffering...and it seems to have an influence on Shinichi that's more than skin deep. As Shinichi fights for control of his body, can he also hold on to his humanity?