"Tachibana Itsuki-kun. Starting today, I'm appointing you the student council vice president." Tachibana Itsuki is a second year high school student attending the Seiga Academy boarding school. As a very ordinary student, he lives an ordinary high school life. Shortly after the second semester begins, Itsuki is suddenly appointed the student council vice president by the universally loved student council president Izumi Rina. His first job as vice president is to investigate the influence of the popular online game "Phantasy Star Online 2" on the students' studies... Itsuki is bewildered as he enters the world of PSO2 with no knowledge of the new bonds or stories that will be born there..

"Itsuki, you're a failure of an ARKS!" Itsuki experiences the joy of PSO2 while working hard at being the student council vice president. While the other members of the student council acknowledge his talents, only student council president Rina has misgivings about his overeagerness. Meanwhile, Suzuki Aika returns from abroad to join Itsuki's class. Aika develops an interest in Itsuki and follows him, causing all kinds of problems. To blow off steam from the real world, Itsuki loses himself in PSO2. However, his coach and veteran player SORO reprimands him for paying too little attention to his surroundings. Unable to understand why he was scolded, Itsuki distances himself from PSO2 for a while, but his friend and PSO2 player Kayano Kota explains to him the truth behind SORO's words.

"This is the guy the regulars mentioned... He's the troll!" In order to experience multi-party play, the true joy of PSO2, Itsuki's friend Kayano Kota introduces him to his friends on PSO2. While surprised by the way they become their characters through roleplaying, Itsuki nonetheless experiences the joy of working together. However, he's also warned about "trolls" who bother other players with their poor behavior instead of helping them. One day, Itsuki finds himself in a group with a player who refuses to help and verbally abuses the rest of the party. He is the troll "Musashi" he'd heard about.

Convinced that she's asking him out on a date, Itsuki doesn't hesitate to agree to go out with Rina. But instead of it being a date, they go to an offline PSO2 event.

"I'm interested in her. I guess I can't just ignore her..." Itsuki's report on the NPCs of PSO2 causes Aika's interest in him to deepen. When people see her following Itsuki around more than usual, rumors begin to spread that they are dating. One day, Itsuki and Rina head to their sister school Tensei Academy to deliver equipment to be used at the Seiga Academy shool festival. However, Aika appears there as well as though nothing is out of the ordinary. Realizing the rumors about him and Aika may have even spread to Rina, Itsuki is disappointed. However, Itsuki and Rina witness a surprising side of Aika when they stop by a shopping mall on their way back.

"I... may have gotten carried away..." Since becoming a member of the student council, Rina's goal has been holding a student-run after party. She has continuously done everything she can to make it happen. After persuading the academy's teachers along with vice president Itsuki, they finally agree to allow it if all the students are for it. But just as everything seemed to be going well, something was happening under the surface. Rina visits Mika's room to investigate her disappearance. The room should be empty, but Aika is quietly standing there.

"He's awakened..." Mika was seen within the world of PSO2. Aika's strange behavior after Mika's return. Itsuki finds the situation suspicious and begins investigating Aika on his own. But from an outsider's perspective, it looksl like Itsuki is chasing Aika around. As Rina and Itsuki make rounds visiting each club's president to make the after party a reality, Aika occasionally comes up in conversation. Itsuki asks his PSO2 friends and keeps looking for Aika, which irritates Rina. Meanwhile, they hear rumors that PSO2 players sometimes go missing.

"Stay out of the fight from now on... You're getting in the way." Itsuki awakens his Photon powers and, with Aika's help, defeats the Darker that appeared in real life. From there Aika takes him inside the world of PSO2 to a room on an ARKS ship. ARKS intelligence commander Kasura reveals to him numerous truths. Though Itsuki is confused by the unbelievable news, he understands what he must do.

"Today and tomorrow let's do our very best to make this the best school festival possible." Itsuki has two lives: fightings against Darkers and high school. Preparing for the approaching school festival and the after party Rina's always wanted to hold has Itsuki exhausted. He does his best to avoid causing any trouble for his fellow student council members, but Rina realizes what he's doing. She asks Aika why Itsuki is so tired, but a series of conversations breeds only more misunderstandings. Itsuki is too busy to even resolve the misunderstanding, but he still does his best as the days pass. The day of the school festival, the Seiga Academy school festival begins with an announcement from student council president Rina. But in the darkness, unbeknownst to anyone.

"Please handle the festival until I bring her back!" The Darkers were after not Tachibana Itsuki but Izumi Rina. By the time Itsuki and Aika realized this, it was already too late. The Dark Falz takes control of Rina and turns its overwhelming power against Itsuki and Aika. Rina doesn't respond in the slightest to Itsuki's pained cries. Itsuki retreats for the moment to return to Seiga Academy. While asking himself what he can do, he heads to the student council room. The student council members are agitated by their president's absence, and they ask Itsuki where she is. Rina's desire is for the school festival to succeed. He doesn't want to disappoint her when she returns. With those thoughts in his heart, Itsuki begs the student council members for help, promising that he will bring Rina back.

"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.