Harry Potter and the Cursed Child, the script of a two-part play that recently opened in London’s West End, is a faithful continuation of Rowling’s series that simultaneously breaks many of her rules. Although Rowling was involved in writing the story, the script is written by Jack Thorne, and the plot hinges on time travel in a way that prompts the question of how much Harry’s creator was involved, with wizards seeking to undo problems in a way that inevitably backfires. While almost all the major characters from the series return in some form or another, they’re less compelling than the two young heroes of the play, Albus Severus Potter and Scorpius Malfoy, the sons of Harry and his former rival Draco. As Albus and Scorpius struggle with living under the shadows cast by their fathers, Cursed Child too seems to wrestle with its legacy, borrowing heavily from older stories while simultaneously challenging the confines of their world.

Reading the next Harry Potter story in script form rather than in Rowling’s fluid, vivid prose was always going to be challenging for readers, so what’s most remarkable about Thorne’s work is how smoothly it flows. At its best, it’s as gripping as many of Rowling’s books were, with suspenseful plotting and twists that are just predictable enough to be gratifying. The stage directions are sometimes sparse, sometimes remarkably descriptive. (Here’s one after a Hogwarts student is drafted by the Sorting Hat: “There’s a silence. A perfect, profound, silence. One that sits low, twists a bit, and has damage within it.”)

The awkward hero of the first half is Albus Severus, Harry’s middle child, dwarfed by both his cocky, popular older brother, James, and his father’s impossible fame as The Boy Who Lived. The fourth scene of the first act, set in “a never-world of time change,” reveals glimpses of Albus’s increasing unhappiness after he arrives at Hogwarts, shows a disappointing lack of magical fluency, and is shut out by his fellow students. His one friend is Scorpius, a disarmingly sweet boy (in his first greeting with Albus, he literally sings about candy) who’s also an outcast because of outlandish rumors that he’s actually the son of … well, you know who.

It would be impossible to come up with a villain as cruel, malevolent, and outright fascinating as Lord Voldemort for the Cursed Child heroes to battle, so it’s almost poetic that Albus’s biggest enemy instead is his father. Thorne’s Harry Potter, all grown up, features prominently in the play, and the tension between him and his son is one of the most frustrating plot points, born out of dramatic necessity and riddled with cliché and angsty platitudes. “I didn’t choose, you know that?” Albus glowers in one scene. “I didn’t choose to be his son.” Later, Harry echoes the sentiment, saying, “Well, there are times I wish you weren’t ...” Although he immediately apologizes, why he feels this way is never really made clear; readers are left to intuit simply that the relationship is a troubled one.