Yuki Yuna is a Hero : Season 1

Yuna Yuki, her best friend Mimori Togo, and sisters Fu and Itsuki Inubozaki, are all members of the Sanshu Middle School Hero Club, which is dedicated to helping those that request it via their website. During class one day, upon each receiving a strange 'forestize warning' message on their phones, the four girls find time has suddenly stopped around them before they are enveloped by a rainbow-colored light, soon finding themselves in a strange colorful forest.

With the Vertex able to regenerate its wounds, Fu has Yuna and Itsuki perform a sealing ritual in order to expose its core. Working together, Fu and Yuna manage to destroy the core, defeating the Vertex and returning everyone to the real world. The next day, Fu explains that she was tasked by her organisation, the Taisha, to grant hero candidates the power to fight against the twelve Vertex that threaten Shinju. Mimori, frustrated that she couldn't help everyone during the battle, directs her

A month following their last encounter, the girls prepare to face off against the fifth Vertex, only for another hero named Karin Miyoshi to suddenly appear and defeat it single-handedly. The next day, Karin transfers into Yuna and Mimori's class, claiming herself to be a fully trained hero sent to supervise the newbies. She reluctantly joins the Hero Club, though is stubborn about becoming friends with the others. That weekend, as the girls plan to meet somewhere, Karin skips out on it, feeling

Itsuki, who gets nervous when singing in front of others, is anxious about an upcoming test, so the Hero Club decide to go to karaoke to help boost her confidence. Meanwhile, Fu is unnerved by a message from Taisha telling her to expect the worst. As she continues to struggle with her nerves, Itsuki thinks about the burden placed on Fu, who has been looking after her ever since their parents died. Later, as Fu laments getting Itsuki involved with the Vertex, Itsuki assures her that she feels

Facing up against all seven of the remaining Vertex, the girls start to fight against the first one, only to be caught in a trap by another, who uses a loud bell to disable them. Itsuki manages to stop the bell, but then three Vertexes merge to form a single more powerful Vertex, proving resilient to their attacks. Not willing to give up, Fu and Mimori use their trump card, the Mankai form, to defeat the combined Vertex, while Itsuki uses her Mankai form to stop a smaller, faster Vertex from

After receiving checkups at the hospital following their battle against the Vertex, Fu is revealed to have lost some vision in her left eye while Itsuki has lost her voice, both of which they assume to be temporary symptoms caused by battle fatigue. However, upon discovering Yuna has also lost her sense of taste and that she herself has gone deaf in her left ear, Mimori fears that these symptoms could be a side-effect of the Mankai form and gets in touch with Fu about it. Meanwhile, Karin, who

Taisha rewards the girls with an all-expenses-paid trip to a hot spring inn during their summer break. The girls enjoy a day on the beach, have a delicious meal, relax in the hot springs, and tell some ghost stories. The next morning, Mimori reminisces about a ribbon she was holding onto when she lost her memory in an accident and wonders if their battles are really over. After the group returns home, making plans for the culture festival on the way back, Fu is summoned to the clubroom where she

After Fu informs the others that their battle isn't over yet, with each girl besides Karin receiving an additional fairy, the girls soon come up against another forestization. Discovering the remaining Vertex, finding it to be overflowing with cores, Yuna quickly disposes of them using the power of her new fairy, causing some worry amongst her friends. When the forest disappears, Yuna and Mimori end up separated from the others, having been summoned by a hospitalized girl, who reveals herself to

Yuna and Mimori relay what they've learned from Sonoko to Fu, who asks them not to tell Itsuki and Karin until they know for certain. Despite hearing from Itsuki's homeroom teacher how Itsuki has been suffering due to her missing voice, Fu remains in denial, hoping that things will eventually get better. The next day, however, Mimori reveals to Yuna and Fu that their fairies were actually created to prevent them from dying, even by suicide, proving that everything Sonoko said to them was true

Mimori recalls the events following the loss of her memories, including her first meeting with Yuna and how they came to join the Hero Club. Having discovered her legs and memory were lost because of the Mankai form and that everything from her standard of living to moving near Yuna was arranged by Taisha, Mimori once again approaches Sonoko, who tells her the true nature of the world. Investigating a hidden barrier facing opposite the Shinju, Mimori goes inside to discover a hellish landscape

Learning Mimori is at the center of the Vertex outbreak, Yuna and Karin chase after her into the barrier, learning what Mimori herself had learned. Before they can try to reason with Mimori, who believes destroying the Shinju is the only way to spare her friends from suffering, Yuna and Karin are forced to retreat from the Vertex.

Yuna is forced to fight against Mimori, who can't bear to lose her memories of everyone like she did with Sonoko, or be forgotten about herself. However, Yuna states her determined feelings to never forget about Mimori and manages to stop her. With the Vertex's final attack headed for Shinju, all of the girls, despite the afflictions caused by their Mankai forms, band together to block the attack, with Yuna delivering the final blow just in time, after which their fairies disappear, ending their