Sensei has a meeting with Black Suit face-to-face. Black Suit reveals that, just like Sensei, he isn't from Kivotos but is part of an organization called Gematria that researches and discovers Kivotos' secrets. Black Suit invites Sensei to join Gematria, but he refuses. He wants to save Hoshino, who is still his student since he never signed and approved her withdrawal letter. Despite his confusion about why Sensei cares about the students, Black Suit gives up and tells Sensei that Hoshino is being held at the Kaiser PMC base.
At Hoshino's suggestion, the Task Force and Sensei decide to go to the aquarium. The girls spend a peaceful time together, as if the days of battle up to that point had been a lie. Hoshino seemed to enjoy herself as much as the others, but Shiroko felt a slight sense of discomfort. Determined, she took a certain action.
Shiroko and the others were confronted by Gehenna Academy's Prefect Team. Their target was Problem Solver 68, a group of problem children at the same school. The Prefect Team demanded they be extradited, but the Task Force refused. Problem Solver 68, who blew up Shiba Seki Ramen, could not be handed over that easily. In the face of the Prefect Team, the Task Force and Problem Solver 68 team up to take action.
After failing their attack on Abydos, Problem Solver 68 are currently preparing for their next move. On the other hand, their leader, Aru, is struggling with the difference between her ideal and reality. Meanwhile, while Shiroko and her team are running away from Black Market, they decide to leave the large sum of money they inadvertently acquired during their heist. During that time, something big happened at Serika's part-time restaurant, Shiba Seki Ramen.
The Abydos Task Force heads to the "Black Market," a famously lawless area, in pursuit of clues about the Helmet Gang that attacked them. While investigating with "Hifumi," a girl from Trinity General School that they happened to meet, they discover a possibility that the repaid money was flowing into a black market. There, Shiroko suddenly shouts, "We're gonna rob the bank!"
The Task Force and Sensei try to solve the problem at hand, but the amount of debt is so huge that they sigh. Unable to come up with a solution, they go into a ramen shop and hit it off with a group of girls who call themselves "Problem Solver 68," a group of outlaws. The next day, however, "Problem Solver 68" begins to attack Abydos High School?!