After the events of Kingdom Hearts III and Re:Mind, Y/N — the female counterpart of Sora from another universe — mysteriously disappears after overusing the Power of Waking to save the people she loves. She awakens in a strange new world filled with heroes, villains, and Quirks: the universe of My Hero Academia. Carrying countless hearts within her and wielding unmatched Keyblade power, Y/N becomes the strongest being anyone has ever seen. Despite her overwhelming strength, she remains kind, optimistic, impulsive, and fiercely loyal to those she cares about. Wearing oversized clothes, chains of glowing keys around her neck, and hiding sadness behind a smile, she enrolls at U.A. High while dangerous darkness begins spreading across both universes.