Mahouka Koukou no Rettousei: Koto Nairan-hen

Zhou Gongjin, who was the mastermind of what happened in the Parasite Doll incident of Nine Schools Competition, has fled from Yokohama to the area of the original ancient magic users group centred around Kyoto also known as the traditionalists.
Since then two months have passed and the National High School Magic Thesis Competition will soon be held again. This year's Thesis Competition is being held in Kyoto sponsored by the Magic Association and in their conference hall.
Tatsuya gets visited by the Kuroba twins who as representatives bring Yotsuba Maya's letter to him. The letter is a request from his aunt saying "I hope for your cooperation to capture Zhou Gongjin".
While it is questionable that whether it is a "command" rather than a "request", Tatsuya and Miyuki go to Kudou's house as they are in the centre as opponents of the traditionalists. As a result, the two siblings have a fated encounter with the "Genius Augmented Magician”.
Conspiracy of the ancient city was the stage. The fate that has continued to smoulder away in the back of the history of magician development, Tatsuya and Miyuki and his companions are challenged.

Adaptation of the original novel's volumes 14-15.

(Source: Mangadex)