With Gin's death weighing heavily on their minds, Sumi and Sonoko are forced to fight another Vertex in the middle of Gin's funeral. Wanting to cheer Sonoko up, Sumi invites her to a festival where they reaffirm their friendship. Later, Sumi and Sonoko receive fairy partners as part of a new hero system, the details of which are only told to their parents. Dragged into another battle gainst three more Vertexes, the girls take advantage of their new abilities and use the power of Mankai to defeat two of them. However, Sumi then discovers she has lost the use of her legs while Sonoko has gone blind in one eye. Despite concern over these inflictions, the girls continue to use Mankai to stop the remaining Vertex from attacking the bridge. After managing to destroy the Vertex's main body, Sonoko follows its core through a barrier, where she witnesses the previously defeated Vertex being resurrected. Sonoko further discovers that her heart has stopped beating but is somehow still alive, while Sumi no longer possesses any memory of her as a result of her second Mankai. Realising that she is no longer capable of dying, Sonoko undergoes Mankai countless more times to protect Sumi from the ressurecting Vertex. Some time later, Sumi, now going under her original name of Mimori Togo, moves into a new home and is befriended by her new neighbor, Yuna Yuki.
激化する敵との戦いに備えて、進化していく勇者システム。しかしそれは小学校六年生の少女たちが背負うには過酷なものだった。それでも少女たちは懸命に、精一杯に、日常を過ごしている。この先に待ち構えている運命が何であろうと、彼女たちの間には永遠に変わらないものが芽生えていた。
Ce film est le dernier d'une trilogie reprenant les 6 premiers épisodes de Yuuki Yuuna wa Yuusha de Aru : Yuusha no Shou et diffusé en qualité d'avant-première.
