***SPOILERS FOR FIRST EPISODE OF NIP/TUCK THIS SEASON***
I missed the last few episodes of last season, so I'm not completely informed on "The Carver," but I take it he attacked Christian, slashing his throat and (I assumed they showed) raping him. This first episode started out with The Carver attacking Christian, injecting him with the drug that freezed his muscles, and then slashing his throat, but also killing him. We see everyone at his funeral, but the gadget that lowers the casket into the ground gets stuck, and there's the awkwardness that such a thing would invoke at a funeral. Then Christian wakes up. He tells Sean that he realizes the dream means he's not ready to let go of what happened to him, and reveals that he was raped. When the female profiler (I think that's what she was) discusses Christian's ordeal with him, though, he denies being raped.
Kimber, of course, doesn't know he's been raped, either, and is angry at him for not having sex with her. She says she wants the old Christian back.
As I recall, Sean's (or I guess, Christian's?) son, Matt, wasn't in this episode.
Julia and Sean argue, as usual, and Julia tells Sean she wants a divorce, that it's time. He tells her he won't give up on them as a couple. He later realizes that he, too, can't let go. Near the end of the episode, he comes to the conclusion that Julia's right, and agrees to a divorce, but Julia was about to tell him she wanted to try to save their marriage. She didn't, after Sean agreed to the divorce.
The profiler believes Christian is hiding details of his attack, and continues to pursue him. Closer to the end of the show, she visits him at home, and soon begins seducing him. He's resistant at first, but you know Christian!

Kimber walks in on them and is like (not a quote; I don't remember exactly what she said) "You can't have sex with me, but you can have sex with some other woman? Who's she?" Christian tells Kimber he's back, introduces her, and they engage in a threesome, with Kimber and the profiler beginning with a kiss.
On a side note, I took a poll on AccessHollywood.com, "Who is your favorite Nip/Tuck character?" Big surprise--out of 2371 votes, 1805 of them (76%) chose Christian Troy (I was one of them

). Second was Sean McNamara (11%). The rest were less than half that!