The prequel to Jujutsu Kaisen (2020), where a high schooler gains control of an extremely powerful cursed spirit and gets enrolled in the Tokyo Prefectural Jujutsu High School by Jujutsu Sorcerers.
Yuuta Okkotsu is haunted. Ever since his childhood friend Rika died in a traffic accident, her ghost has stuck with him. But her spirit does not appear as the sweet girl Yuuta once knew. Instead, she manifests as a monstrous and powerful entity who fiercely protects him. Unable to control Rika's violent behavior, Yuuta is helpless to stop the bloodshed that follows from her brutal vengeance. As a result, when apprehended by "Jujutsu" sorcerers--the secret guardians of the world, trained to combat forces like Rika--Yuuta wishes to be completely isolated so that no one else can get hurt. Yet his apprehender, the master sorcerer Satoru Gojou, has different plans for him: he will join Jujutsu High School and learn to control Rika in order to help people. Now a first-year at this school, Yuuta starts to learn Jujutsu arts and combat malignant beings. Alongside his new classmates Maki Zenin, a Jujutsu weapons expert; Toge Inumaki, a spellcaster who uses his words as weapons; and Panda, a seemingly walking and talking panda bear, Yuuta begins to find his place in the world and, for once, to feel comfortable with his abilities. However, as his training progresses, Yuuta comes to learn that the dangers of the Jujutsu world go far beyond that of wicked spirits.
High school student Yuta Okkotsu is frequently bullied, but one day his bullies are gravely injured by a Cursed Spirit that clings to him. The higher-ups of the Jujutsu Society wish to have the boy killed, as his curse is a dangerous spirit. However, a teacher at Tokyo Jujutsu Technical High, Satoru Gojo, recruits Yuta to join the school in November 2016, thus saving him. Yuta explains that the Cursed Spirit is Rika, a childhood friend whom he had promised to marry when they grew up. Rika died in a freak accident and became an overprotective spirit that harms anyone who threatens him. Yuta meets fellow students Maki Zen'in, Toge Inumaki, and Panda, all with distinct abilities of their own.
During his first mission with Maki, Yuta successfully summons Rika on his own for the first time to save them from a Cursed Spirit. Three months pass in his school training, and he grows close to Maki, Toge, and Panda. One day, on a mission together, Toge and Yuta are attacked by a high-level Curse. The man behind the attack was Suguru Geto, a previous student and old friend of Gojo, who defected from the school and killed over a hundred innocent people on a mission.
Geto attempts to get Yuta on his side so they can make use of Rika, but Yuta refuses when he insults Yuta's friends due to unsettled circumstances. Geto declares war to activate a portal to the under-world: he will release a thousand Curses upon the city to remove non-sorcerer humans, as he believes them to be undeserving and beneath sorcerers. Geto's real reason for the war, however, is to distract Gojo so he can kill Yuta and add Rika to his collection of cursed spirits. Gojo realizes this upon learning of Yuta's background, and sends Inumaki and Panda back to the school to protect Yuta and Maki during the night of Geto's attack. Geto overpowers them all, leaving only Yuta conscious. Enraged at seeing his friends hurt, Yuta promises himself as a sacrifice to Rika in order to strengthen their bond. As a result, Geto is severely wounded. He is found by Gojo, who after reflecting on their past friendship, executes him.
Gojo confirms that Yuta was the one who inadvertently cursed Rika through UN-specified ties to royal bloodlines within the hierarchy of Japan's caste system, rather than the other way around, by being unable to accept her death. Yuta broke the curse after promising himself to Rika, and she is able to pass on peacefully after Yuta continues training as a sorcerer within the institution.
In a post-credits scene, Geto's former ally Miguel eats lunch with Yuta in Kenya, and Gojo comes to join them.
