5 ways Harry Potter's Fantastic Beasts could tell the story of young Dumbledore and the rise of Grindelwald

"This is where I always wanted to go," author and Fantastic Beasts screenwriter JK Rowling says in a sneak peek at the film, released during a worldwide fan Q&A session.

But where can she go with the tale? Well, the possibilities are endless.

Rowling could take us through the origins of the major conflict between Grindelwald and the wizarding world

We know Gellert Grindelwald was finally defeated by his old pal Albus Dumbledore in 1945, many years after he assembled an army of supporters who helped him take over Europe and build Nurmengard prison during a wizarding conflict that gripped the continent.

“While I busied myself with the training of young wizards, Grindelwald was raising an army,” said Albus Dumbledore, who we know is teaching Transfiguration at Hogwarts when Newt Scamander sets sail for America.

The first Fantastic Beasts and Where to Find Them film opens in 1926, when Grindelwald was presumably amassing a group of followers, so it’d be the ideal time to get a feel for what he and his co-conspirators were up to.

Is this the back of Grindelwald's head in the new trailer for Fantastic Beasts?

America's Ministry of Magic head honcho, Macusa President Seraphina Picquery makes reference to the rise of Grindelwald in Europe and she sure does seem worried about it.

She even fears his actions could lead to an all-out wizarding war...

We’ve always assumed those blokes in dark outfits with wands in the trailers were aurors, but what if they’re actually Grindelwald supporters?

What if they're attacking Muggles and wreaking havoc to try and break the International Statute of Secrecy?

Could it be them, not a magical creature, that lay waste to Shaw's election rally?

And could it be Grindelwald's supporters who create or summon that ominous red dusty thing that's floating above Time Square?

The films could explain how even the most respectable wizards fell under the spell of a charismatic mastermind

In Harry Potter and The Deathly Hallows, Aberforth Dumbledore recounts the tale of the day his sister, Ariana, died.

“Didn't I understand, my poor sister wouldn't have to be hidden once they'd changed the world, and led the wizards out of hiding, and taught the Muggles their place?” he recalls Grindelwald telling him.

Director of Magical Law Enforcement Percival Graves tells Credence (whose adoptive mother is one of the Second Salemers attempting to expose witches and wizards) that if someone succeeds, they’ll be forced to stay in the shadows forever, adding that they've both “lived in the shadows for too long”.

Could he be talking about the Second Salemers? Or Macusa? Graves seems unsure as to whether the strict Macusa status quo really protects wizards or Muggles, so in theory, breaking the International Statute of Secrecy and putting the mere mortals in their place could appeal to him.

I mean, it even appealed to Albus Dumbledore at one point. He once wanted to do things "for the greater good" - who's to say Graves doesn't quite simply get sick of the way Macusa punishes wizards who break their rules and head on over to team up with Gellert?

We could learn a little more about the Deathly Hallows

We know Grindelwald was so obsessed with getting his hands on all three Hallows that he adopted their symbol for his own personal mark. He engraved it on the walls of Durmstrang before he was expelled and made it his own version of Voldemort's Dark Mark.

Now we know it has some sort of connection to Graves too. But is that because he’s hunting Grindelwald’s supporters? Or because he’s one of them?

We could meet a young Albus Dumbledore

We already know the sad tale of Albus, Gellert, Aberforth and Ariana, but after that day in Godric's Hollow we have very little information about what happened between Grindelwald and Dumbledore.

The Hogwarts headmaster talks of waiting too long to face his old friend, for fear of discovering that he'd killed his own sister, so there's now room to explore how Dumbledore dealt with Grindelwald's rise to power.

If Graves is a Grindelwald supporter, it could explain why he says Dumbledore's name with a slight hint of disdain when speaking to Newt during his interrogation.

And there's also room to tell the story of a young man who was very much in love with the friend he'd lost to a quest for power and immortality.

And lead us right up to the beginning of Harry Potter as we know it

"I open at the close," is one of Rowling's favourite phrases, after all. Who's to say Harry's story didn't begin at the end of another BIG tale...