What would Hogwarts be like without Hermione Granger?

That's what a lot of Harry Potter fans are asking themselves these days, thanks to a hashtag, #WithoutHermione, that has been making the rounds on social media. It got started after the Harry Potter Alliance, a group of Harry Potter fans and activists, released a heartbreaking "acceptance letter" from Hogwarts earlier this month.

Courtesy The Harry Potter Alliance

"To the finder of this letter," it reads. "We are pleased to inform you that you have been accepted to the Hogwarts School of Witchcraft and Wizardry Waitlist. Unfortunately, we are not able to allow you to come to Hogwarts at this time.

This is no reflection on your abilities and we hope you find comfort in knowing you are not alone. Around the world, thousands of girls are not permitted to attend school, or are unable to finish their schooling due to discrimination, tradition, poverty, or violence."

The letter was released as part of a partnership with She's the First, a nonprofit that helps girls become the first people in their family to graduate from high school (and a partner of Glamour's The Girl Project). Around the world, 50 million girls are being kept out of secondary school, for a ton of different reasons: Some are pressured to get married and have children while they're still young; others live too far from a school or can't afford the tuition fees; still others can't go to school because they have to work to support their family. Even in the U.S., girls are being socialized out of STEM programs and targeted with unfair dress codes.

Just think about it: What if Hermione had been subjected to that treatment, and she hadn't been able to go to Hogwarts?

"Hermione was constantly saving the day in ways you didn't even realize and making a difference in ways you didn't even notice," says Katie Bowers, whose real, actual title is campaigns director for the department of magical causes and correspondence at The Harry Potter Alliance.

"There are so many things that we don't notice that we're missing out on because girls aren't in the classroom—that's a huge amount of potential," Bowers says.

Bowers pointed out that, in the first book, at Harry's very first Quidditch match, Harry probably would have died if Hermione hadn't interrupted the spell that was being cast on him. Basically, if it weren't for Hermione, everyone would have died. Voldemort would have conquered the wizarding world. Evil would have triumphed.

Obviously, that's a distressing thought for Potterheads, who have been taking to social media to catalog the countless ways Hermione stepped in to ward off catastrophe.

What's just as distressing is the thought of the millions of girls who aren't getting a quality education, like Hermione did. As Bowers said, "There are millions of other Hermiones in the world, and we are missing out on their ability to save the world."

To help those budding heroes, you can donate to She's the First via the #WithoutHermione campaign. The campaign's page also has tips on how to get involved.