There's sterility in luxury. A couple dozen best-selling novels in the bag and you don't have to worry about coming home to a three-by-five foot apartment, the walls peeling with a thousand-and-one memories of sob stories left before. Castle's apartment is professionally furnished, expertly tailored, and, right now, the last place he wants to be.

He's been wandering the West Side for a good part of the evening, trudging through remnant snow slush, his silhouette cut against great clouds of bunker steam. At around ten he starts to feel the cold and actually hails a cab, giving the driver the address as easily as if it were his own. Detective Beckett's apartment is an impressive edifice wedged between two brownstones, its tan marble like an exclamation point between two dull expressions of punctuation. He pays the driver and gets out, his breath puffing in front of him, filling the wide blue collar of his coat. Her lights are on. This late, that's either a very good -- or a very bad -- sign.

His pull with her doorman gets him through to the lobby and from there it's just a short (jolty) elevator ride to Beckett's floor. A light is out at the far end of the hall, close to Beckett's door. If Castle believed in portents (he had occasion to, every once in a while), he would see this as a sign.

He raps gently on her door.