Albus and Scorpius discover a mysterious time-turner and use it to travel back in time, inadvertently altering the past and creating an alternate timeline where Voldemort has not been defeated and the evil remains. Albus and Scorpius must race against time to restore the original timeline and set things right, all while grappling with their own personal struggles and the weight of their families' legacies.
Throughout the journey, Albus and Scorpius embark on various time-traveling adventures, encounter familiar characters from the original Potter series, and uncover deep secrets and revelations about their past and identities. As they strive to repair the damage they have caused, they learn the true meaning of friendship, courage, and facing the past to shape a better future.