Dumbledore wasn't exactly an open book in the Harry Potter movies – he was more often than not a riddle, wrapped in a mystery, locked away inside a Pensieve – but that won't be the case in Fantastic Beasts: The Secrets of Dumbledore.

A new trailer for the Fantastic Beasts threequel reveals more of Albus Dumbledore's (Jude Law) plan to stop Dark Wizard Gellert Grindelwald (now played by Mads Mikkelsen) from taking over the world. With Crimes of Grindelwald having revealed that Dumbledore can't move against his one-time friend due to a blood pact, he must outsource his dirty work.

Thus, Magizoologist Newt Scamander (Eddie Redmayne) is called upon to lead this iteration of Dumbledore's Army, including Newt's brother Theseus (Callum Turner), Newt's assistant Bunty (Victoria Yeates), Ilvermorny professor Eulalie "Lally" Hicks (Jessica Williams) and muggle baker Jacob Kowalski (Dan Fogler).

But Grindelwald is growing his own legions, which include Ezra Miller's Credence Barebone (or is it Aurelius Dumbledore?) and Alison Sudol's Queenie Goldstein.

David Yates is once again at the helm, directing from a script written by J.K. Rowling and longtime Harry Potter screenwriter Steve Kloves (who has penned every adaptation except for Order of the Phoenix.) The costumes, meanwhile, come courtesy of Colleen Atwood, who won an Oscar (her fourth) for Fantastic Beasts and Where to Find Them.

Fantastic Beasts: The Secrets of Dumbledore apparates into theaters on April 15.

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