
Note: There are spoilers for Season 3 in this post, as well as a discussion of the status of the Castle/Beckett relationship at the end of Season 4 and the first episode of Season 5.
This season picks up right where last season left off. Beckett is being whisked into a hospital emergency room. She took a bullet to the chest from an unknown shooter at the end of Season 3. After a tense scene, she is going to survive (although it wasn’t ever really in doubt.)
What was in doubt was whether Beckett would remember Castle’s confession to her, just after she was shot, that he loved her and he couldn’t lose her. She says she doesn’t, but it is revealed in the first episode that she really did. Her therapist (Michael Dorn) tries to help her address this, as well as the trauma of almost being killed.