NEW YORK — The pop culture juggernaut of J.K. Rowling’s Potter-mania appeared to be breathing its last gasp when the eighth film in the series, part two of “Harry Potter and the Deathly Hallows,” made its premiere amid teeming throngs of bittersweet Potter fans in London’s Leicester Square in 2011.

Wands went into their cases. Hogwarts scarves were hung up.

“When `Potter’ finished, I thought that was it,” says producer David Heyman, who oversaw the movie adaptations from the start and has since produced “Gravity,” “Paddington” and other films. Director David Yates, who helmed the final four Potter movies, staggered away for a much-needed holiday.

“I wouldn’t have imagined that I’d come back so quickly,” says Yates. “But it was the script that pulled me back in.”

The script was “Fantastic Beasts and Where to Find Them,” and it, unlike all the Potter films, was penned by Rowling herself. Based on Rowling’s 2001 book, which was framed as Harry’s Hogwarts textbook, “Fantastic Beasts” is set in Rowling’s familiar, magical world, but takes place 60 years earlier, in a more adult 1926 New York where wizards and Muggles (called “No-Majs,” as in “no magic,” in America) live in disharmony.

This fall, Rowling’s $7.8 billion film franchise will roar back into life, resurrecting one of the most potent and lucrative big-screen sensations. It’s a two-pronged attack. While “Fantastic Beasts” is reaching back into the past of Rowling’s Potter world, the two-part West End play “Harry Potter and the Cursed Child” (only co-written by Rowling) is going into the future. It moves the tale 19 years ahead of where the books left off.

Authorship, timelines and casts may be extending in new directions, but the old obsession is still goblet-of-fire hot. The script of “Cursed Child” sold two million copies in two days.

Big expectations naturally also surround “Fantastic Beasts” (Nov. 18). For Warner Bros., which has endured sometimes rocky times in the intervening non-Potter years, it’s a happy reunion. In today’s constantly rebooting, ever-sequalizing Hollywood, did you really think Rowling’s world was finished?

“This isn’t Harry Potter. There aren’t Harry Potter characters in this,” says Heyman. “But there is connective tissue. To (Rowling), it’s part of one big story.”

That connective tissue, like a prequel, will grow more pronounced in coming “Fantastic Beasts” installments, eventually leading close to Harry, himself. A trilogy is planned, with the next chapter going into production next July. Less diehard fans should prepare for some very hardcore nerding-out by Potter fans as they trace illuminating hints in the tale’s history.

Eddie Redmayne stars as the bumbling magizoologist Newt Scamander, the future author of the Hogwarts textbook. Katherine Waterston, Dan Fogler and Colin Farrell are among the many supporting roles. The story about escaped magical beasts loose in a city with anti-magic elements, the filmmakers claim, bears contemporary relevance.

“We are in a time of great bigotry in America, the UK and around the world,” says Heyman. “This context of the story, while not political with a capital ‘P,’ is relevant in this time. It’s an entertainment but it’s not a hollow entertainment.”