Japan’s “idols” — musical entertainers (usually performing in groups) with specific cultural mores — have long been fodder for anime, from psychological thriller “Perfect Blue” to mega-franchise “Love Live!” The latest entry to the canon, “Trapezium,” which hits theaters in Japan tomorrow, lays claim to a certain amount of authenticity: It’s based on a book penned by Kazumi Takayama, a former member of the group Nogizaka46.

The novel, published in installments between 2016 and 2018, centers on a high school freshman named Yu Azuma (voiced by Asaki Yuikawa), whose dream is to create an idol group from scratch. A meticulous student of idol culture, Yu realizes every group needs a gimmick. Hers will be to recruit one girl from each of her region’s four high schools, located to the north, east, south and west.

Yu carries out her plan with guile, visiting each school and ingratiating herself by appealing to her targets’ interests. She throws a tennis match to Ranko (Reina Ueda), helps Kurumi (Hina Yomiya) win a robotics competition, and joins Mika (Haruka Aikawa)’s volunteer group — all while keeping her true intentions secret. Before long, the four are fast friends, and thanks to some behind-the-scenes maneuvering by Yu, they appear on local television and gain the attention of an idol producer.