The story Jujutsu Kaisen follows the life of Itadori Yuji an ordinary boy with inhuman physical abilities.
It then shows the character Megumi Fushiguro who comes to his school to find a special grade cursed item, but he finds it to be missing but feels it as Itadori runs past him.
Itadori was running to the hospital to meet his grandfather, who had passed away when Megumi finally caught up to him.
Apparently, he and his friends were curious, so they wanted to take a look at the item, but it wasn’t in any sort of protection, so it wasn’t exactly hard. However, unfortunately, the item was still with his friends who were staying at the school after hours, and Itadori just had the container.
Megumi and Itadori run back to school, and on the way back, Megumi explains to him that the item, which is a thousand-year-old severed finger, is a special grade cursed item with special traits and is extremely dangerous. They arrive to see that a curse had escaped because of the finger, and it was gonna kill the two students who were Itadori’s friends.
Megumi jumped in to save them while Itadori was still outside, surprised by the sudden monsters he was seeing but decided for himself that he wasn’t going to lose anyone and jumped in through the window to see Megumi struggling with one of the curses. He kicks the monster, which in turn leaves his classmate and follows him to the roof, where Itadori gets caught.
In a moment of desperation, Itadori swallows the finger.
Megumi was furious because there was no doubt that the person who did something as stupid as this would die, but there was a 0.1 person chance which is the worst possibility.
That possibility is that the curse to who the finger belonged, which oh so happens to be Sakuna ‘The King of Curses’ will be able to possess the body of the one who ate his finger.
A moment passes, and suddenly Itadori frees himself from the clutches of the curse, killing it, and he floats in the air for a second before coming to the ground with weird markings on his body like Sukuna.
As Sukuna is finally awakened after a thousand years since no one had a body strong enough to be a vessel for the curses king, he looks around, but Itadori surprisingly gets his body back by his will, surprising Sukuna and Megumi.
Just then arrives Gojo, who is Megumi’s teacher with a bag of sweets in his hand as souvenirs and not the least bit worried for his injured student; he instead takes pictures to show the second year then he finally asks where the cursed finger is to which he replies that Itadori ate it.
When Itadori agrees, Gojo asks him to bring back Sukuna for ten seconds, to which he is hesitant at first. Still, Gojo relieves his worries seeing as he is the strongest Jujutsu sorcerer who tells them he would even be able to take on the king of curses in his full strength which is all his eaten fingers.
Gojo fights Sukuna with the upper hand, and Itadori comes back after ten seconds and loses consciousness.
He wakes up with Gojo in front of him.
Gojo explains to him that the higher-ups wanted to get Itadori killed right away since he could be dangerous but Gojo himself had suggested keeping Itadori alive since he is a person who can actually hold Sukuna as a wessel and they might not get another chance like this in the next thousand years, and since Sukuna’s fingers are indestructible if Itadori eats them and they execute him, they would be able to get rid of Sukuna’s threat once and for all.
Gojo asks Itadori if he wants to help them with the plan or not, but basically, it was just die tomorrow or die later. But Itadori wanted to help people and decided he could do it by taking the threat of Sukuna away from the world.
Itadori goes to a test where he gets asked questions about what motivations he has to join them, and he also fights a little and eventually passes the test.
Bow Itadori has officially become a first-year jujutsu sorcerer who tracks down curses and takes them down. Itadori is a first-year along with Megumi under the mentorship of Gojo Satoru, and he moves into the first-year jujutsu form with Megumi.
After they go, they also meet up with their third fellow first year and teammate whose name is Nobara Kugisaki, and Gojo promises to take them to show the city, seeing as Nobara and Itadori haven’t seen it before, making them really excited but instead brings them to an abandoned building with a curse in it to see the two new members’ abilities, disappointing the pair, and since Itadori can’t use a jujutsu technique yet, he gets given a cursed weapon to use instead.
Nobara and Itadori succeed in taking out the curse with Nobara rare yet useful hammer jujutsu style and Itadori’s incredible physical ability, and they end up becoming friends.