to the men who killed her mother. And her suspicions are eventually confirmed when DNA found on the victim matches DNA from the assassination attempt on her life just a year before. This is the break she has been waiting for. She finally has a lead on whoever shot her and therefore a lead on whoever was behind her mother’s killing.
Castle, less enthused, is worried about her. Remember, secretly he has been working on her mother’s murder for months and protecting her from the shadowy men who want to keep lying dogs laid. When he receives a phone call fromMontgomery’s old friend – the one who has a secret cache of information on the bad guys and who has been working as a go between from them to Castle – warning Castle to get Beckett to back off or else, Castle goes to Beckett’s apartment.
It is there that he tells her about the friend and the backdoor deals he has made to save her, because “he loves her. But she already knows that.” Beckett is furious that he would go behind her back, but she does not deny that she has known about Castle’s feeling this whole time. From the way the scene is played out, I think she understands why Castle did what he did. She comes off more indignant than outraged. All the same it does not change her mind. She is going to move forward on this case whether Castle likes it or not. Castle tells her that she will have to work without him then. He can’t watch her get herself killed. And he ends their partnership. Two steps back, sh*t hit fan. Told you so.
Throughout all of this Ryan, Esposito, and Beckett discover that their victim had taken a job from an old military buddy to break into a home (Montgomery’s) and steal a bunch of files for quick easy money, money that he and his family desperately needed.