The Harry Potter franchise featured many intricate storylines and hidden details that only well-versed fans could pick up on. Reading J.K. Rowling's books helped to explain certain links between some uncertainties in the story of Harry Potter. From the mystery behind the prophecy to why Fred and George never saw Peter Pettigrew on the Marauder's Map. Many aspects of the movies only made sense after close inspection of the details in the Harry Potter book series. How the Sword of Gryffindor wound up in a frozen lake in Harry Potter and the Deathly Hallows - Part 1 appeared to be one of those mysteries in the movies.
Source：https://www.cbr.com/sword-of-gryffindor-lake-harry-potter/
