In 2086, Naunax, an extraterrestrial mothership housing 50,000 life-forms who identify as Simurians, appears above Earth. The Simurians wield powers akin to those of Japan's jujutsu sorcerers, prompting all diplomatic negotiations to be redirected to the Japanese, who are charged with determining whether coexistence is feasible. Despite confronting a special-grade incident comparable to Sukuna Ryoumen's assault 68 years earlier, humanity welcomes the aliens—for the time being. Fearing that these potent beings might declare war, Japan consents to a Simurian envoy accompanying jujutsu sorcerers to school and on missions. Two teenage sorcerers—Yuuka and Tsurugi Okkotsu, siblings and grandchildren of the deceased Yuuta Okkotsu and Maki Zenin—are selected to partner with Marulu "Maru" Val Vol Yelvori, a friendly, three-eyed Simurian. With both sides concealing vital information yet desiring eventual harmony, the burden falls on Yuuka, Tsurugi, and Maru to uphold the fragile peace and avert mutual destruction.