"Making the school festival a success with the student council president... Isn't that right, vice president?" With the help of Kota and his other PSO2 friends, Itsuki and Aika arrive at the Dark Falz. Meanwhile, in the real world, the student council members and their classmates are doing their best to make the school festival a success. All that's left is to wait for the star to return. However, the obstacle standing in their way is immense and overwhelming. Itsuki and Aika struggle to find a way to rescue Rina from the Dark Falz that now wields overwhelming power having acquired a vessel. With the ARKS attack approaching as well, there's no tiime to lose. Itsuki takes his chances and enters the Dark Falz in an attempt to rescue Rina.
Itsuki Tachibana is a student of Seiga Academy, a co-ed boarding high school with excellent reputation, located in a suburb outside the city center. On a day of second semester, he was summoned by Rina Izumi, the most esteemed and praised chairperson, to the student council room, without knowing what awaits him.
