The Fifth Holy Grail War continues, and the ensuing chaos results in higher stakes for all participants. Shirou Emiya continues to participate in the war, aspiring to be a hero of justice who saves everyone. He sets out in search of the truth behind a mysterious dark shadow and its murder spree, determined to defeat it. Meanwhile, Shinji Matou sets his own plans into motion, threatening Shirou through his sister Sakura Matou. Shirou and Rin Toosaka battle Shinji, hoping to relieve Sakura from the abuses of her brother. But the ugly truth of the Matou siblings begins to surface, and many dark secrets are exposed. Fate/stay night Movie: Heaven's Feel - II. Lost Butterfly continues to focus on the remaining Masters and Servants as they fight each other in the hopes of obtaining the Holy Grail. However, as darkness arises within Fuyuki City, even the state of their sacred war could be in danger.

Shuuichi Kagaya is what one would consider an average high school student, but sometimes, he turns into a monster. He doesn't know how or why he got his abilities, only that he would prefer no one knows about them. One night, he finds a building ablaze with a girl trapped inside. Deciding to save her, he transforms and carries her to safety, but accidentally drops his phone. The next day, the girl he saved—Claire Aoki—finds him and confronts him about his monster identity. She even goes so far as to push him off the school roof to prove her theory after Shuuichi denies her allegations. Desperate to save himself, he transforms, and Claire snaps a picture in order to blackmail him into telling her everything he knows about monsters, which, ironically, isn't much. As it turns out, Claire has a secret of her own: she has been searching for her sister, who also became a monster. She enlists Shuuichi's help to track her down, but they aren't the only ones searching for answers.

Since the discovery of Samon Syndrome 30 years ago, thousands of young people have traveled to fantasy worlds, the few returnees managing to keep the special abilities they acquired in those parallel universes. Akatsuki Ousawa, known as the Rogue Hero, discards his peaceful life in the fantasy world Alayzard to face new challenges upon returning to Earth. He comes back with Miu, the daughter of the Demon King he defeated, and is now forced to hide her true identity by having her pose as his little sister. The two soon join Babel, a special school designed for those who have acquired special abilities and magical powers through their journey to a fantasy world. Babel was seemingly founded to train young interdimensional travelers and guide them to the right path for the sake of humanity and themselves, but its true purpose remains unclear to the pseudo-siblings. Will Akatsuki and Miu be able to overcome the hostile, powerful student council and uncover the forces at play behind the scenes?

Kenjaku, the one known as Noritoshi Kamo and most recently as Suguru Getou, has initiated the next step in his destructive, thousand-year plan of ordinary humans' evolution and eventual eradication. The jujutsu world higher-ups reinstate 15-year-old Yuuji Itadori's execution, as Satoru Gojou is incapacitated as a result of Kenjaku's master plan in Shibuya. While Yuuji is unaware of this, he patrols the abandoned Tokyo streets with Chousou, exterminating any and all cursed spirits in his way. Meanwhile, the bigoted and arrogant Naoya Zenin's pride takes a hit when Megumi Fushiguro is selected as the Zenin Clan's next head. To draw out Megumi and eliminate him, he goes after Yuuji—but Yuuta Okkotsu is set on being Yuuji's executioner. Kenjaku's Culling Game—a rigorous battle royale spanning throughout Japan and forcing the jujutsu competitors to kill each other—is set in motion, and the young jujutsu sorcerers join the fray to settle old scores, free Gojou, and liberate the jujutsu world from the threat that is Kenjaku.