Time-Turner

We first saw the Time-Turner with Hermione Granger in the third book and film, Harry Potter and the Prisoner of Azkaban. Originally, it was meant to help her manage her school workload, which was more than she could handle normally. In the end, she used it to save the life of Sirius Black and the hippogriff Buckbeak. We later encountered Time-Turners, their mechanics, and their history in the script for J.K. Rowling's play – Harry Potter and the Cursed Child.