"Is this love, Agent Romanoff?"

"Love is for children."

She has blood on her hands. She has daggers in her eyes. She has ice in her heart.

Some say she doesn't have a heart.

She is a cool, calculated killer. An assassin of the highest degree. A robot, some say. Feelings do not compute. Especially not something as weak and vulnerable as love.

Love is impossible. She has grown up too fast, opened her eyes too fast. She let go of her childhood dreams too fast. Everything has moved too fast for something as slow and building as love.

Love is for children.

It may be hard to imagine, but Natasha was a child, once. Once upon a time, she was a bright-eyed little girl, a child with dreams as big as any other. She doesn't like to think about why such dreams were pushed aside. To her, it happened too quickly, too painfully, to bother remembering. It is the past, she tells herself. It will stay the past.

The past bothers her all too often though. Her ledger, bleeding and scarlet, haunts her, reminding her. Her nightmares make her wake up screaming soundlessly. Soundlessly, because it is all too easy for someone to hold such acts of weakness over her head, drowning her without a care.

Natasha is a cool, calculated killer. She is not weak. She is anything but weak.

But when those blue eyes look at her, blazing, she has to lock her knees to keep them from trembling. There is so much feeling in those eyes that cannot be seen in his often blank face (too much feeling), it is almost foreign. Because Natasha is a cyborg (supposedly) and it's all too true that feelings are a distant, pushed-away weakness.

It almost seems like an excuse. Too fast, too painful, too often, too easy. Too much. It's worn out and meaningless, but she continues to use the same old phrases (excuses?) because they are reliable, easy to fall back on. In her chaotic world, she needs this constant, this reliable and easy and too-much and too-little, and it's her way of remaining the cool and calculated killer she is supposed to be.

Because Natasha has been unmade before. Not just broken, torn apart at the seams, smashed and shattered and shredded, but completely unmade. It is not a pleasant experience, she will tell you. There will be no emotion in her voice, except maybe a hint of dryness that will somehow make you practically parched, hiding the raw, wet pain that she carries. Because no one can know that Natasha Romanoff has feelings.

Except him.

Clint knows. Clint can see right through her. Right through her and into something else, something that even she isn't always aware of. He can see pain, but more than that, he can see her determination, her weaknesses, her courage and her fear. He sees her. Not the cool, calculated killer. Her.

And she sees him. She sees his guilt and his pride, his passion and protectiveness. It's almost like she has x-ray vision set specifically for him, the way she sees through his impenetrable armor, just as he sees through hers. They both have small balls of energy and compassion and pain hidden away underneath walls of blood and bone and bullets and arrows. They are similar, she knows, and that is why they are drawn together. There is no one else in the world so like her and him.

She'd never admit it, but she is grateful for Clint.

He was sent to kill her. He was sent to eliminate her. She was a threat. But when he made that call, when he didn't get rid of her, everything changed. It made her feel vulnerable, at first, the way she was so transparent to him. It made her feel powerful, at first, the way he was so clear to her. All of a sudden she was feeling things again.

She hid it away, and soon her reputation around SHIELD was as the cool, calculated killer, an enemy turned ally – definitely not friend, because friends have feelings. Agent Romanoff did not have feelings.

Which brought the question: was a she friend of Clint's? Was he her friend?

She realizes that yes, they are friends. Possibly each other's only friend. Yet he is also so much more than that. He is her best friend. He is her partner.

Natasha uses the same old excuse whenever it seems like she is caught. It is almost as worn and meaningless as the too-fast-too-painful-too-much excuse. I owe him a debt.

She paid him back years ago, really. Saved his life like he spared hers. It is just an excuse. A tattered, hollow excuse that is used too much. She knows it is a lie, and it slips out too easily, but what can you expect from a spy and a killer? Nothing less, she knows. She knows it all.

And when he is gone, when all the feelings come rushing back just below the surface, when she is about to explode from the almost-almost-almost foreign sensation, she knows. She utters the same lies, tricks the monster – that wasn't a lie, even if it seems like one from her immediate reversion to that cool, calculated killer – into revealing his plan, but she knows, she knows, that everything is changing all over again. She pushes out a new lie, or maybe it is the truth, but it feels wrong and right and the feelings simmer and bubble and scratch at their prison when there is nothing on the outside but a blank face.

"Love is for children."

(Natasha forces back the memories of small, chubby hands and the feeling of a bright smile and all those dreams. She is not a child. Not anymore.)

But then Clint is back, and everything is slow and building only for a moment (slow and building, like love, but no) before time flies by, too quickly. They are suddenly in the midst of a battle, adrenalin pumping in their veins, warming their icy hearts. They face not-so-similar risks almost every day of their lives, as spies and assassins, but this seems different. And Natasha realizes that she knows now, but she thinks she will never admit it.

Then all of a sudden the battle is over, they won, and she and Clint are alone now, just them and the possibilities and the slow, building something. And not only does Natasha know, but she is painfully aware. She won't admit it. She can't. There is just too much at stake, and they're both so used to their armor that even though they can see right through each other they never take it off. The small bundles of feelings underneath the bloodied hands and sharp eyes and icy hearts grow almost out of control. She still will not admit it, not now.

But eventually, Natasha has to admit that if love is for children, then somehow, impossibly, deep down, she is still that bright-eyed child from a lifetime ago.

And that's alright with her.