When QUARTET★NIGHT is chosen to perform as the Triple S Opening Artist, they decline the opportunity after ST☆RISH and HE★VENS give equally compelling performances. Raging Otori and Shining Saotome propose another musical showdown to determine the opening artist between the three groups in which all three of them must sing songs written by Haruka! Who will win the decisive concert and the honor of performing at the Triple S?