She's Agatha when they first meet in Paris – auburn hair, polished nails, and a dress that doesn't leave much to imagination. His preference usually goes to men, but there's something about her that makes him forget his mission for a while; she's good at it, he decides in the stifling heat of a dingy motel room as he loses himself in her over and over again.
She's Georgia when she shoots a man to save his idiotic little brother – brown hair, a black outfit, and the unerring aim of a sharpshooter. He acknowledges her with a sharp nod, her eyes never blinking as she meets his gaze; a moment later she's gone, a shadow flitting through the shadows of the night.
She's Mary when he gives her a new identity – blonde hair, a soft smile, and an English accent that isn't actually her own. They share one last kiss in the privacy of his office, right before he tells her about her assignment; she wants a different life, he needs someone to keep an eye on John Watson, and they're both willing to take a calculated risk.
Until everything goes spectacularly wrong, and he's forced to reconsider his previous decision.