Some time in 1999, I noticed that one of the kids in a family I was baby-sitting had spent the entire day in her room. “Anna, are you okay?” I asked, cracking the door.

“Yes!” she exclaimed. “I’m reading the best book. It’s about a school called Hogwarts where you learn to be a wizard, and the pictures on the walls talk!”

That was my introduction to Harry Potter, the fantasy series that would help define the millennial generation — many of whom grew from childhood into adolescence right along with Harry, Hermione, and Ron. J.K. Rowling’s seven books were the last great hurrah of the pre-digital publishing industry, and seven faithful-to-a-fault movies duly struck box-office gold.

For a few years we all took a breather. The books came out in new editions, the movies came to rest like tired owls on DVD shelves around the world, and Universal built theme parks. Rowling turned her energies towards adult novels, with mixed results.

Now, Harry Potter is back — except not really, not in his familiar youthful guise. An epic two-part play about Harry and his classmates as adults opened this year, to acclaim, in London. The published script (by playwright Jack Thorne, with Rowling collaborating on the story) became a bestseller and won critical raves to boot. Though it’s less directly concerned with Harry himself, Rowling’s second offering this year raises the redux stakes.

Fantastic Beasts and Where to Find Them, a film by director David Yates (who directed the last four films in the Potter series proper) with a screenplay by Rowling, was inspired by a reference book read at Hogwarts. Rowling published a print version of that book as a charity project in 2001, and the film explores the story of the book’s wizarding-world author Newt Scamander (Eddie Redmayne).

It’s the first in a reported five-film series, so Rowling is back in comfortable territory: writing long-form narratives that unfold in episodes, with constant foreshadowing and flashbacks. Even if the story isn’t as immediately appealing as that of Mr. P, Rowling’s storytelling skill is such that Fantastic Beasts works in many of the same ways, and captures a similar sense of wonder.

The Harry Potter films — particularly the later ones — are notable for how unapologetically impenetrable they are to anyone not familiar with the books, and even working with a story not previously told in book form, Rowling and Yates keep up the galloping pace. Fantastic Beasts assumes you know the basic tenets of Rowling’s fantasy world, and if you don’t, you might want to buy tickets for a couple of screenings in succession.

The British Scamander disembarks in New York circa 1926 with a suitcase full of magical creatures. He aims to return one of them to its native habitat in the desert Southwest, but his plans quickly become irrelevant as he and his escape-prone pets are caught up in the local supernatural drama.

America turns out to be, like Britain, full of witches and wizards who choose to hide their powers from muggles — or, as they’re called in the States, “no-majes.” (It feels pointed, but apt, that the American equivalents of British slang terms are as literal and flat in the magic world as they are in the mundane world.)

Things get complicated quickly, centering on efforts by MACUSA (that would be the Magical Congress of the United States of America, which also seems to headquarter the magical U.N.) to apprehend a mischief-making Obscurial (a poltergeist the size of a house, with an origin story I won’t spoil here). Newt and a no-maj he befriends (Dan Fogler) fall in with a pair of magical sisters (Katherine Waterston and Alison Sudol) who are on the outs with MACUSA.

By the time everything shakes down, you’ll be wracking your brain trying to remember all the references to the Harry Potter books. Why is that name familiar? What does that symbol mean? What was that character’s backstory again?

Fantastic Beasts works as a prequel because a central part of the appeal of the original books was the fact that Rowling knew her world in all directions, and wasn’t afraid to drop hints and references that weren’t fully developed. In that way she’s similar to J.R.R. Tolkien, whose Middle Earth is so fully formed, you feel like The Lord of the Rings might have actually slipped through a wormhole from a universe where those adventures actually happened. The Harry Potter books have much the same effect, and it dovetails with the conceit that wizards and witches are in fact all around us: they’re just hiding.

Compared to the Harry Potter books, though, Fantastic Beasts has an uphill battle for our affections: the protagonists aren’t adorable children, they’re fully-grown adults. Newt himself is an endearing presence, the red-cheeked Redmayne bashfully peeking out from behind his flop of curly hair. The doughy Fogler wins us over too, with help from Rowling’s affectionate characterization and Philippe Rousselot’s honey-toned cinematography. There are also some fearfully intimidating characters, including Colin Farrell as a relentless MACUSA enforcer and Samantha Morton as a “Second-Salemer” who wants to snuff witchcraft out at any cost. Unfortunately, Waterston’s character is underwritten (as well as, perhaps, miscast) — and a romantic flame between Fogler and Sudol strains credibility.

Well, if there are to be four more movies, Rowling has plenty of time to build on what she’s started here. She’s certainly earned my attention for another installment: in a season where the flagship fantasy movies have relied on visual wonders rather than crisp scripts (see: Doctor Strange, Arrival), Rowling’s attention to detail comes as a relief. She knows where every winding corridor goes in this world, and just as crucially, she knows where it ends.

Fortunately, this twisting tale is just getting started. Pass the popcorn.

– Jay Gabler