They're killing our magic. Hermione, one of the greatest magical scientists to ever live, finally solves the power issue. The purebloods thought it was the mud that weakened the magic. They were wrong.
Hermione Granger is one of the greatest scientist witches to ever live. In the magical community, scientist usually means someone who invents spell. To her, it has always been about figuring magic out.
Magic, which is completely illogical.
She found that very quickly, and gave up. She doesn't do that very often, but she's not so arrogant as to think her experiments are going to be better than dozens of others who came before.
Hermione moved on to the power issue: the root of both the Dark Lord's Wars. The purebloods thought it was the muggleborns dirtying their magic. The muggleborns thought it was all in the pureblood's heads. Where was the proof that wizards eight hundred years ago were all more powerful than those today?
They were both wrong.
The muggleborns, Hermione found, were a sort of meter. The more there are, the more powerful magic is.
Hermione is thirty-four years old.
There hasn't been a single muggleborn in the last twelve years.
She is very afraid.
The first thing Hermione finds is the magic's source: the Earth itself. Maybe it's the molten core, or heat, sound, chemical, solar energy pulled from everything, or even just a field of ! permeating everything. But the Earth supplies their magic.
This is where the problem starts.
Because the muggles are killing the Earth.
Maybe they knew, Hermione thinks. Long ago, someone found out as I have. And they said, We shall use candles, and parchment, and quills. We shall not kill our magic with oil and paper and plastic.
We shall not kill our magic.
Who forgot to tell the muggles?
If they'd never seceeded from muggles, this might not have happened. Somehow, maybe they could've stopped the muggles from killing their home.
The Earth will someday be enveloped by the sun, the muggles say, and before then we will have to move to a new, Earth-like planet.
There will be no magic on that planet. The wizards will have died out. Magic will be gone from the world.
With a heavy heart, Hermione ties her report to the owl, pets its soft feathers, whispers, please forgive me. She sets her note to Ron on the kitchen table, and is glad their kids aren't living with them anymore. They shouldn't have to see this.
My body is in the spare room, the note reads. Read the Prophet, and I hope you'll understand what comes next. I can't live knowing what I have done.
For a moment, Hermione had hope that her fellow witches and wizards would react reasonably. They would reveal themselves to the muggles, explain what was happening, offer to help fix it. The world would go on (until the sun went supernova, of course), and things would be great. No pollution. Maybe even no hunger, no disease.
The fantasy ended, and she knew what she had to do.
This is where my loyalties lie, now.