Johnny Depp as Grindelwald and Poppy Corby-Tuech as Rosier in Warner Bros. Pictures’ fantasy adventure “Fantastic Beasts: The Crimes of Grindelwald.” Photo: Warner Bros. Pictures, HO / TNS Photo: Warner Bros. Pictures, HO / TNS

“Bunty, the baby nifflers are loose again.”

And with that, the hero of “Fantastic Beasts: The Crimes of Grindelwald” signals to his housekeeper — and to the audience, really — that this new chapter in the adventures of magizoologist Newt Scamander (Eddie Redmayne, as mumbly and bumbly as ever) will have at least one antic chase scene featuring CGI critters.

But there’s something — or, rather, someone — far less adorable that has also escaped in this Harry Potter prequel, which takes a turn for the dark side that will satisfy the franchise’s adult fans even more. As the film opens, in a bravura, wham-bam prologue that combines action with shivery terror, the title character, an evil wizard played by Johnny Depp, is seen escaping from detention while being transferred from a New York prison to face punishment for unspecified crimes in Europe.

What crimes? Possibly his haircut: a peroxide-blond brush cut that makes Depp look like a scoutmaster for the local chapter of the Hitler Youth. More seriously, he wants power.

Once Grindelwald lands in Paris, Newt — a glorified dogcatcher, clearly out of his league — is dispatched to go after the fugitive wizard by his former Hogwarts teacher, Albus Dumbledore (Jude Law). Why doesn’t Dumbledore, one of the most powerful wizards who ever lived, go after Grindelwald himself? Ahh, you’ll just have to wait to find out.

“Fantastic Beasts: The Crimes of Grindelwald” Rated PG-13: for some sequences of fantasy action Running time: 134 minutes 3 1/2 stars (out of five)

Newt is aided in this mission by sidekicks returning from the 2016 “Fantastic Beasts and Where to Find Them”: baker Jacob Kowalski and magical sisters Queenie and Porpentina — known as Tina — Goldstein (Dan Fogler, Alison Sudol and Katherine Waterston). J.K Rowling, who wrote this surprise-filled screenplay for veteran Potter director David Yates, has a real knack for names. The film’s other key character, also returning from the previous film, is a young man named Credence Barebone (Ezra Miller).

As we learned in the previous installment, Credence is an Obscurial; a wizard who has repressed his magical abilities, which, in his case, have manifested themselves in the form of an Obscurus: a dark, uncontrollably destructive entity. Rowling is also quite clever with subtext, the Obscurus being a wonderful metaphor for the unhealthy neurosis that can develop when you deny your true self. There are also political overtones here — as there have been in every other Potter book and film — in the hostility and persecution that exists between Wizards and the nonmagical Muggles, also known as No-Majs. That polarization is a metaphor for the modern world if ever there were one.

Credence is being pursued by Newt, who wants to neutralize the power of the Obscurus, and by Grindelwald, who wants to harness it to suppress the No-Majs. That battle forms the crux of the film, around which all else revolves, including romantic subplots involving Jacob, Queenie, Tina and Leta Lestrange (Zoë Kravitz).

Credence, for his part, is also on a hunt. An apparent orphan who was raised by No-Majs, he wants to discover his true identity. And boy, will he. “The Crimes of Grindelwald” has one of the biggest third-act reveals in the whole Harry Potter series.