Natasha isn't sure when she sees it. The mild-mannered doctor, travelling the world in a dusty suit curing diseases for free, has a dark side. A wolf beneath his sheepskin.

It hits her in the face when he yells at her.

Stop lying to me.

In a voice that wasn't human, a voice too otherworldly to be explained. A voice with green eyes and green fists and an anger problem. A cornered monster.

And for one of the first times in her life, she is scared. She is terrified.

Because Black Widow can take on any man. Odds are always on her side. There's always skill in her corner. She doesn't rely on things as stupid as luck and prayer. She relies on herself, because she is the only one she can trust.

But this. This monster. She can't fight. This beast will kill her. She could try to hide. She could try to run. But her vision would inevitably end in a haze of green.

Because the only thing she sees in this monster is a reflection of herself. What she can become. What she has become before. Might become again.

But Bruce Banner is something all together different. A cornered monster raises its head, raises its voice, rips at the seams. But it's all for show.

He gets what he wants, exposes her for the liar she is, sees her for what she is. Another cornered monster.

And he smiles.