The acclaimed British playwright and screenwriter Jack Thorne was already 18 when J.K. Rowling released the first of her Harry Potter novels, and he was in his early twenties when he started reading them. But like many adults — with and without children — Thorne found himself quickly sucked into the story of the orphaned young wizard, his friends, and their fantastic struggles against destructive forces.

“I consumed the books whole,” says Thorne, who is making his Broadway debut with Harry Potter and the Cursed Child, which opened April 22 at the Lyric Theatre. “I was a rabid Potterhead, and remain one.”

So it didn’t require a lot of arm-twisting to enlist Thorne to write Cursed Child, already a massive hit in London, where the production has won a bevy of honors including nine Olivier Awards — more than any other production in the history of Britain’s biggest theater prize. Thorne collaborated on the story with Rowling and the celebrated stage director John Tiffany, with whom Thorne had previously worked on an adaptation of the vampire novel Let the Right One In.

“The three of us met and started talking, and kept talking for six months,” Thorne recalls. Given the vast popularity of the Potter series, in films as well as on the page, “I expected some resistance, but there was no ‘This is who Harry is, this is what it has to be.’ I couldn’t have asked for two finer collaborators.”

Thorne was intrigued by “the legacy and cost of being Harry Potter, and luckily John and Jo [Rowling] were just as interested in that. Where you are as an adult is so defined by the journey you went on as a child, and here you have a child who didn’t really have any parental figures; he had a number of guardians, but no parents. And he also had an obligation to save the world. I can’t imagine what that would have been like.”

Presented in two parts — which fans ideally can watch on the same day or in consecutive evenings, or at nonconsecutive performances as an alternative — Cursed Child follows the grown-up Harry, a husband and father of three employed by the Ministry of Magic, now overseen by his childhood friend Hermione Granger. As Potterheads will recall from the epilogue of Harry Potter and the Deathly Hallows — set 19 years after the series concludes, which is where Cursed Child begins — Hermione is now married to another member of the posse, Ron Weasley, and Harry is married to Ron’s sister, Ginny. Hermione and Ron are also parents of a daughter named Rose, and Harry’s old nemesis Draco Malfoy pops up with a son, Scorpius, a close friend of Harry and Ginny’s younger son, Albus.

Though it’s possible to buy tickets for just one show, the full arcs of these characters (and others, with accompanying twists) can be appreciated only by viewing the whole play. In Rowling’s original series, Thorne points out, “every single book challenges the characters and does something incredible with the plot. That’s why they’re so loved. I was constantly aware of the expectations when we were conceiving this play, but Jo would not let a bad plot happen.”

While crafting Cursed Child, Thorne was in the process of becoming a parent himself: He and his wife “were going through several rounds of IVF” that eventually produced a son, now nearly 2. “I think you can smell the fear of being a parent on every page of the play,” he muses.

Indeed, both Harry and Albus must grapple in the play with both the legacy that fascinated Thorne and with more common challenges faced by teenagers and men in early middle age. “The books were about three kids who were pretty good at dealing with being in school,” Thorne notes. With Albus and Scorpius, he sought to “write about two kids who don’t fit in at Hogwarts,” the school of witchcraft and wizardry that is their parents’ alma mater. Ironically, Harry’s son is “probably not as immediately likable” as Draco’s, Thorne concedes. “Scorpius is a lovely boy. But Albus is full of goodness; it just doesn’t show itself right away. You so often see kids portrayed as either angels or arseholes, but I’m interested in kids who aren’t either.”

It was Rowling’s idea to put the grown-up Hermione — played by a black actress, Noma Dumezweni, who is one of seven original cast members brought from London to Broadway (including those playing all previously mentioned roles, except Rose) — in charge of the ministry. “Our first question was, What are these characters from the books doing now? And Jo knew right away. And it’s not just the fact that Hermione is a woman; she’s also the daughter of Muggles” — that is, nonmagical parents, outsiders in the realm of witches and wizards — “and the most powerful figure in the wizarding world.”

In bringing Cursed Child to New York, Thorne was also keen to “bring Ginny’s story slightly more to the front,” he says. “The partnership between Ginny and Harry is something that was really enjoyable to examine and write about.”

Those who have seen or read Cursed Child know that other characters, new and old, are featured in the play, with attendant surprises. A #KeepTheSecrets campaign has helped reduce spoiler spills since the London premiere, though Thorne realizes that more people are likely familiar with the story at this point. “But for me, the play works best when you don’t know what’s going to happen next,” he says. “I think it’s really cool that people will walk into the theatre not knowing the story, and see this amazing journey.”

Pictured above from left to right: Colin Callender, John Tiffany, J.K. Rowling, Jack Thorne, Sonia Friedman. Photo by Jenny Anderson.