While holding a Christmas party at her place, Sonoko unveils an ancient book titled "The Hero Annals", detailing the records of the first heroes. In the year 2018, three years after the first appearance of the Vertex, five girls; Wakaba Nogi, Yuna Takashima, Tamako Doi, Anzu Iyojima, and Chikage Kori, are all chosen as the heroes who would protect everyone, alongside shrine maiden Hinata Uesato. After one of their missions leads to the death of Tamako and Anzu, Takashima receives serious injuries as a result of backlash from using her trump card to try and enact revenge, while the aftermath puts a lot of stress on Chikage.