There’s no denying that Harry Potter is one of the most magical series ever written, but even J.K. Rowling herself has admitted that the story has a few plot holes.

But while some of these mysteries — such as that of the entire Time-Turner storyline — will likely remain unsolved, a number of the more frustrating inconsistencies have been explained away in the years since the books were published.

From the presence of Peter Pettigrew to the conspicuously invisible Thestrals, here are five major Harry Potter plot holes with resolutions.

The truth comes out

When Rowling launched her new website in December 2016, she included a FAQ section to clear up some confusion about the first movie in her new wizarding world saga, Fantastic Beasts and Where to Find Them, as well as a few lingering questions about the Potter series. One of these queries revolved around why Veritaserum — a.k.a. the most powerful truth serum in the wizarding world — isn’t used by the Ministry of Magic to interrogate suspects.

“It is, but skilled wizards can avoid its effects by using antidotes and charms. A gifted Occlumens could also resist Veritaserum,” Rowling wrote, referring to those, such as Severus Snape, who are skilled at shielding their minds from invasion.

Among other details, this explains why Veritaserum couldn’t be used to weed out the real Death Eaters from those who claimed they had only done Voldemort’s bidding under the influence of the Imperius Curse following the First Wizarding War.

What about Wormtail?

Considering Fred and George Weasley nicked the Marauder’s Map from Filch during their first year at Hogwarts, it seems strange that they never noticed Peter Pettigrew — who was still posing as Scabbers the rat — sleeping in Ron’s bed every night once their younger brother arrived at school. However, in a June interview with The Huffington Post, Oliver Phelps, who played George in the movies, provided a (somewhat jokey) answer to this conundrum.

“Maybe it’s a boo in the family that no one talks of. ‘Who’s this Peter bloke?,'” he said. “Maybe it was an unspoken word in the Weasley’s family.”

The case of the missing Thestrals

When Harry arrives at Hogwarts for his fifth year in The Order of the Phoenix, he realizes that the school’s carriages aren’t drawn by magic, but rather a flock of Thestrals. Luna Lovegood — who can also see them — then explains that the Thestrals are now visible to him because he witnessed Cedric Diggory die. “They can only be seen by people who’ve seen death,” she tells him.

However, some fans have pointed out that since Cedric died during the Triwizard Tournament, it seems like Harry should have been able to see the Thestrals when the carriages transported him to Hogsmeade station at the end of The Goblet of Fire.

But in a 2004 interview at the Edinburgh Book Festival, Rowling maintained that this wasn’t an error.

The letters that I’ve had about the Thestrals! Everyone has said to me that Harry saw people die before he could see the Thestrals. Just to clear this up once and for all, this was not a mistake. I would be the first to say that I have made mistakes in the books, but this was not a mistake. I really thought this one through. Harry did not see his parents die. He was one year old and in a cot at the time. Although you never see that scene, I wrote it and then cut it. He didn’t see it; he was too young to appreciate it. When you find out about the Thestrals, you find that you can see them only when you really understand death in a broader sense, when you really know what it means. Someone said that Harry saw Quirrell die, but that is not true. He was unconscious when Quirrell died, in Philosopher’s Stone. He did not know until he came around that Quirrell had died when Voldemort left his body. Then you have Cedric. With Cedric, fair point. Harry had just seen Cedric die when he got back into the carriages to go back to Hogsmeade station. I thought about that at the end of Goblet, because I have known from the word go what was drawing the carriages. From Chamber of Secrets, in which there are carriages drawn by invisible things, I have known what was there. I decided that it would be an odd thing to do right at the end of a book. Anyone who has suffered a bereavement knows that there is the immediate shock but that it takes a little while to appreciate fully that you will never see that person again. Until that had happened, I did not think that Harry could see the Thestrals. That means that when he goes back, he saw these spooky things. It set the tone for Phoenix, which is a much darker book.

On destroying Horcruxes

Described by Rowling on her website as, “an oldie about Chamber of Secrets that I’ve been asked at least once a week for nine years,” the mystery in question concerned the Horcrux inside Harry surviving his encounter with the Basilisk in the second book of the series. Because Basilisk venom is one of the few substances that can destroy Horcruxes, some readers apparently wondered why the part of Voldemort’s soul residing in Harry wasn’t destroyed when he was bitten by the giant serpent.

Of course, the ever-wise Rowling was able to shed some light on the matter. “A Horcrux can only be destroyed if its container is damaged beyond repair, Harry was healed by Fawkes,” she wrote, referencing Dumbledore’s beloved phoenix. “Had he died, the Horcrux would indeed have been destroyed.”

And when a fan pointed out that the Resurrection Stone still worked for Harry after Dumbledore used Godric Gryffindor’s sword to destroy the Horcrux inside Marvolo Gaunt’s ring, the author provided some further explanation. “The crack in the stone was irreparable,” she tweeted. “Only Dumbledore [could] have extracted the soul fragment but left the original charm intact.”

The corruption of Quirrell

Since Voldemort was reduced to a shell of his former self after attempting to murder baby Harry, some fans were confused as to how he was able to get the young Professor Quirrell under his control in The Sorcerer’s Stone. But in the 2016 Pottermore eBook Short Stories from Hogwarts of Power, Politics and Pesky Poltergeists, Rowling explained that the Defense Against the Dark Arts teacher was “turned into a temporary Horcrux,” — a possession that showed up in the appearance of the Dark Lord’s face on the back of Quirrell’s head — which made him unable to resist the will of the “far stronger, evil soul inside him.”

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Write to Megan McCluskey at megan.mccluskey@time.com.