Harry Potter And The Deathly Hallows’ magical mirror shard is a big narrative hole that the movies fail to explain. Rowling’s books provide insight.

The two-way mirror shard from Harry Potter and the Deathly Hallows was one narrative hole that puzzled moviegoers unfamiliar with J.K. Rowling’s book series. The Harry Potter series is noted for its rigorous continuity.
Given how much substance had to be eliminated for the films. The screen adaptations are excellent representations of the texts. However, the film’s explanation for a magical two-way mirror shard carried by Harry throughout The Deathly Hallows Parts 1 and 2 was brushed over. Despite the fact that it proved to be a life-saving plot element.
Harry possessed a little fragment of the mirror in Harry Potter and the Deathly Hallows, and he began to see glimpses of who he believed was Albus Dumbledore. When Harry and his companions were confined at Malfoy Manor. Harry used the shard to summon Dobby.
Harry Potter and the Deathly Hallows: Two-Way Mirror
They found Dumbledore’s brother, Aberforth, holding the rest of the mirror in The Deathly Hallows Part 2. Aberforth revealed that he obtained it from Sirius Black’s residence through Mundungus Fletcher and had been following Harry on his quest to uncover Voldemort’s Horcruxes.
The presence of the mirror, as well as why Harry possessed a fragment of it. How Harry (Daniel Radcliffe) knew it used to belong to Sirius Black, and how Aberforth knew he could use it to monitor Harry’s safety, were all left unanswered by the movie.
Because it was not presented in Harry Potter and the Order of the Phoenix. This magical artifact was only briefly described in The Deathly Hallows films.
The film’s deletion of a seemingly unimportant element from the novel in which Sirius provided Harry. A two-way mirror that allowed them to talk. While Harry was at Hogwarts caused a big gap in the Harry Potter universe’s typically rigorous storytelling.

The pair of two-way mirrors were more crucial narrative elements in the novel version of The Order of the Phoenix. Their introduction to the series early on better prepared them for their later roles in The Deathly Hallows. Because the two-way mirror set given to Harry by Sirius Black was not utilized in the novel. The sequence was removed from the film adaptation.
The fact that the mirrors were not used. On the other hand, turned out to be a narrative element in and of itself. Harry had opted not to use Sirius’ gift, fearing that he would only embarrass his impulsive godfather.
After the events of the Department of Mysteries and Sirius’ death. Harry only recalled his mirror at the conclusion of Order of the Phoenix.
Harry Potter and the Deathly Hallows
He destroyed his mirror after realizing that. If he had used it to check on Sirius before traveling to the Ministry of Magic’s Department of Mysteries instead of depending on Floo Powder. He would still be alive. A piece of the broken mirror ended up in Harry’s school van, which he discovered years later during the events of The Deathly Hallows.
At the time, leaving the mirrors out of The Order of the Phoenix film looked like a minor oversight. It is a tribute to Rowling’s meticulous preparation that such little items may become so significant two volumes later.
First-time viewers concentrate on the action. Last Harry Potter films are unlikely to question the sequence of events that transpire only due to the existence of the inexplicable magical artifact.
The near omission of the two-way mirror, on the other hand. It was perplexing for fans of Harry Potter and the Deathly Hallows and other Harry Potter films who had never read the novels.
The complete explanation was omitted from the films. The significance of the mirror and its emotional link to Sirius was far more complex in the novels.