This is what happens in Finny's past, as shown in episode 21 of Kuroshitsuji.
Disclaimer: Sadly, Kuroshitsuji doesn't belong to me. This is just a fan fiction, and a result of my overactive imagination at 2:00 in the morning.
Fly Away
I sit in the middle of an empty, cell-like room, staring up at the tiny window set high into the wall. It's the only window in the room.
Everything is concrete: the bars crossing over the window; the bare walls with cracks running down them like tearstains; the cold, grey floor that's rough underneath me. Only the door isn't concrete, but it's a sturdy oak that I'll never be able to open on my own.
The floor is so cold that its coldness seeps right into me, freezing my veins so that pure ice courses through them. I'm numb with it, even my terror caught in its hungry claws so that it's like a memory frozen in the back of my mind.
It's dark in my prison but for the one sliver of light that angles down from the window. I stare at it yearningly as if it's the last time I'll ever see sunlight. For all I know, it could be. That's part of the reason why I can't peel my eyes away from it. If I do, someone will come and take it away, blow the light out like it's the flame of a candle, and I'll be plunged back into absolute darkness and fear. Then my last precious memory of life before will be gone, just like that.
If I listen carefully, sometimes I can hear birdsong from outside. It's an alien sound, but I treasure it. It's a part of life before. I stare out the window as if in a trance, my eyes fixated on the teeny patch of blue I can see. I've forgotten what it's called. Water? No, not water… sky.
That word is alien, too.
A bird hops onto the ledge outside the window and trills a few notes. Its speckled brown feathers are spotted with dirt and the fuzz on its head and chest has bald patches, but it's the most beautiful thing I can ever remember seeing. It cocks its head at me, black eyes bright with curiosity, and I listen as if hypnotized to the string of melodies coming from its beak.
It's a sad, sad song that it is singing. It makes me want to cry, but I can't remember how. I can't remember how to smile, either.
I vaguely wonder if I will ever see sunlight again—not the faint, flickering ghosts of sunlight that are trapped in the room with me, but real sunlight that burns my skin like hot kisses. Will I ever go outside again?
I try to remember what the wind blowing through my hair feels like.
The bird whistles, its tiny claws scratching on the stone ledge.
I love birds. But I hate them, too. They bring back memories, painful memories of life before that They told me to forget.
As if my thoughts have summoned Them, I hear footsteps outside of my cell. The bird tenses, startled, and then flutters away in a chaos of feathers and alarmed shrieking as the door to my cell bursts open. Blinding white light floods in—artificial light, too-bright light that makes red and black spots dance across my vision. Against the brilliant glare are the silhouettes of Them.
I don't know who They are, but I'm terrified of Them. They do things to me, hurt me. They poke me with needles and inject sickly-looking fluids into my body. They are cruel with their crisp white coats and their syringes and clipboards, their stern faces grim and impassive.
Now the one in charge steps towards me with a jacket draped over his arm, which is odd, because why would They care if I'm cold and freeze to death or not? Then he's forcing it on me and I realize that it's not a normal jacket—the sleeves are too long—he's wrapping and tying them around me—forcing my arms to hug my chest—and the word comes to me—a straitjacket, that's what it's called—
I'm fighting, kicking and clawing and biting, but there's more of Them than me, and They're stronger—
Some time in the middle of the struggling, I must hit my head, because I black out. When I come to, the straitjacket is gone. I'm strapped down to the table I've become so familiar with, They are all looking expressionlessly down at me, and one of Them is holding a syringe. This time, instead of being a sickly green or yellow, the fluid is a dirty reddish-brown colour, like rust. The thin, silver tip of the needle glints in the fluorescent lighting, just as cruel and cold as Them.
"This will boost his strength," the one in charge says, and the others smile eagerly, encouraging him on.
Then he's inserted the needle into my thigh and is pressing down the plunger, and it doesn't matter anymore that I've forgotten how to cry and smile because suddenly I've discovered that I can scream.
The ice in my veins turns to the concentrated heat of flames, boiling through me so that I think I'm going to burn from the inside out. The fire rages through me with a torrent of searing heat and white-hot agony. Sweat rolls off my skin and soaks my clothing, my hair, everything.
And They are still touching me, holding me down with their rubber-gloved hands, trying to restrain my thrashing as the straps that hold me to the table snap in half. My back arches, the fire coursing up my fine to my neck, my head. Someone's sliced me open with an axe and has poured hot acid over the wounds, and it's eating away at my flesh—that's what it feels like. I scream and scream and scream with a voice I'd forgotten I had and They are throwing Themselves on top of me to keep me down now that the straps are useless. I'm their silly experiment gone wrong and They can't let me escape.
The agony has faded to a dull roar in my veins that throbs with every beat of my heart. Now the panic sets in, and the anger, and the desperate desire to survive, to escape, to fly away like that little bird—
Escape-escape-escape-escape-escape-escape—
Strength, that's what They shot into me this time. It will be their undoing.
I throw Them off of me, breaking up and out from under the sea of urgent hands, and fling one away with me. I don't even push hard, but he goes flying into the nearest wall and slides to the ground with his neck twisted at an odd angle. I flinch at the crack of the impact, but then more of Them are coming and I roll of the table, crushing some under me. I kick and punch and pummel my way through Them and burst through the door into a long corridor. Now I'm running, my feet a blur that move relentlessly to the pounding rhythm of my heart, leaving Them all behind… leaving the shouting, the pain, the prison…
The whiteness dissolves as I hurl myself through the last doors into the hot glare of sunlight—real sunlight, and that's a real breeze that's ruffling my hair. I can't even scream or laugh or cry because I'm so elated—I'm free, I'm free, I'm free, I'm free—
I look up and see my bird soaring in the wide blue sky in the distance. I take off after it, leaving the darkness and nightmares behind me, running into the sunlight so fast that it's almost as if I've learned to fly.
Whoever said that humans can't fly forgot that if you put your mind to it, you can do anything. Even grow wings.