Two months after the Scorched Halloween incident, Tatsuya and his friends hold a going-away party for Shizuku who will be studying abroad in America. With the start of the new semester, an exchange student from America arrives at First High School.

A string of bizarre murders occurred where the victims were found to have most of the blood drawn from their bodies. Due to the methods used by the killer, they were called "vampire incidents," and similar incidents were also occurring in America.

The vampire that attacked Leo was a demon called a "parasite." The Saegusa and Jumonji families decide to join forces to solve this case. Mikihiko and Erika search for the parasite to get revenge for Leo, and they confront a mysterious masked magician.

It turns out that the masked magician that engaged in a sword fight with Erika was Lina. With her identity blown, Lina uses the Parade spell to attack Tatsuya. Tatsuya attempts to disable the Parade spell by dismantling it but fails.

A parasite is an information body that was generated from the spirit dimension. How could an entity from another dimension appear in the physical world? An evil visitor of unknown origin infiltrates its way into First High School.

Colonel Balance orders Lina to capture the caster who was behind Scorched Halloween. Balance gives Lina a custom-made device called "the Brionac" which converts Strategic-Class magic into a beam of high-energy plasma.

The Yotsuba Family intervenes to eliminate all threats to Tatsuya from the USNA military forces. The only threat that remains are the parasites. After questioning Pixie about the remaining parasites, Tatsuya heads to Aoyama Cemetery with Miyuki and Honoka to lure them out.

Thanks to Pixie's psychic powers, Tatsuya and his friends are finally able to capture the parasites. They leave the scene after Erika and her team arrive, but a third faction disguised as the police appear before them and get in their way.

As instructed by Raymond, one of the Seven Sages, Tatsuya and his friends head to the outdoor training area behind First High School on the night of February 19th. Just as Raymond said, they detect the presence of all active parasites and Lina gathering at the scene. At this rate, clashing with Lina, who is hell-bent on completing her mission as Sirius, will be inevitable. With complex emotions at play, the final battle with the parasites begins.

About a month after the parasite incident, Tatsuya and his friends reluctantly bid farewell to Mayumi, Mari, Katsuto and the other seniors at the 29th graduation ceremony at First High School. The time also comes for them to give a send-off to another friend who came from America.

Tatsuya and Miyuki are invited to a party to commemorate the completion of Japan's first hyper-building offshore tower, there Hayama introduces a young girl called Sakurai Minami. The two are shaken upon seeing her face which is that of a woman who died in an incident three years earlier. At such a time, there is intelligence that the party is being targeted by extremist magic advocates — The Advancement of Humanity Front.

The Advancement of Humanity Front have declared they will ‘blow up the offshore tower in one hour’. But there is no guarantee they will keep to their one-hour time limit. For the sake of preventing the Advancement of Humanity Front’s scheme, Tatsuya takes Miyuki and Minami towards the control centre on the first underground floor.