A/N: Because Eurus is fascinating and haunting, and deserves a fic.

The little girl in the plane never flies into the city. The city wouldn't want her, wouldn't know her, they'd only know the smoking, twisted refuse. She would be burned, and they would not find her.

The plane. It was a plane that took her to the hospitals where they tested her. That is why she knows what it feels like. Uncle Rudy sat beside her. He held her hands.

He held them down.

.

Sigmund Freud called it an iceberg. But people know what lies on the bottom of the ocean; nobody quite knows what's at the edge of the universe.

The girl in the plane could tell them, but they are all sleeping. All sleeping, with their eyes open.

She's always liked taking eyes out. If people aren't going to use them, they shouldn't have them.

They shouldn't have anything.

.

She thinks she can feel love. She can feel everything. It isn't that. It's never been that. But most people stop when they feel things; she keeps going. And if you keep going, everything is the same.

.

Sherlock, though. He's the only thing that's different.

.

Moriarty is very pretty, in the slow, deliberate, slick way that blood is pretty when it pumps right out of a vein.

He could have spurted whole arteries, though, if you'd known him longer than five minutes. Tick tock. His brother the station master was pulled apart by one of his own trains.

Moriarty said he almost cried, it was so funny.

She had asked, Do you miss him? and he rubbed his hands over his eyes, pulling the skin tight.

Only before he died, he said.

.

Maybe Sherlock has to die, so he can miss her.

Moriarty says he can arrange it. The fall doesn't kill you; Eurus knows this. If Sherlock can fight the landing, fight all the landings—

She'll know he was as different as she hoped.

.

Hope. She thinks she can hope. Hope makes you angry, when you drop it. Hope is what hurts people, what hurt little Victor in the bottom of the well. He kept calling.

She should have killed him quicker.

The girl on the plane is screaming, screaming, screaming, and Eurus bites at her, fiercely, to make her be quiet.

.

The old beech tree—

The tree, Mummy said, was dying.

But Eurus wanted to be able to tell.

.

Sherlock is nicer. Sherlock is better. He always was, and she always loved him. At least, she thinks she was supposed to or wanted to know how.

You can kill anybody, anybody. They only wake up right before they die.

(Sherlock keeps nodding off. Falling asleep. You had to kill him, but they took you away before you could wake him. It wasn't fair. It wasn't fair.)

Hope. Sentiment. She doesn't understand those things, but she must have them, Sherlock has them, if she just cuts the right part—she'll see how they work.

.

Because sentiment, after all, is a chemical defect.

And Eurus knows all about those.