I don't remember too much, but from what I can recall, the main character, Meng Xinghun(?) is an assasin of this organization and gets his assignments from Madame Gao(?). He feels depressed about his like and job because he sees no point. Then one day he sees this girl with lonely eyes named Xiaodie(?).
click to show/hide spoilersAnd of course, some romance sparks. Then he finds out about her secret, that she has a kid and was married and other stuff about her family background(?). Then somewhere along the plotline, he gets betrayed or finds out he's been lied to by his boss. He finds out about some sort of conspiricy? Okay, I don't really remember how the rest of the plot goes...