In Misaki City, Crimson Realm beings drain life energy from humans, countered by Flame Hazes like Shana, the fiery protector. Her focus shifts to Yuuji Sakai, a boy caught in their battle. As their bond deepens, Yuuji contemplates Shana's hidden emotions amid their daily struggles. Things escalate when a mysterious transfer student arrives, triggering a race against time. With the Bal Masqué looming, Yuuji and Shana must confront their feelings while investigating the enigmatic 'Midnight Lost Child' within Yuuji.