Always

When Castle and Beckett attend the murder of a reformed gang member, they find evidence that links him to Beckett's shooting and the theft of documents from Roy Montgomery's home. The 12th Precinct is divided as Castle tries to stop Beckett from investigating, causing a rift in their partnership. Her efforts are unsuccessful, and Cole Maddox (Tahmoh Penikett)—her would-be assassin—escapes, vowing to kill her once he recovers Montgomery's files on his employer. Esposito and Beckett are suspended for withholding information on the case, however Beckett decides to resign. Beckett then goes to Castle's home where she finally gives in to her feelings for him, and they share a passionate kiss. The episode concludes with the mystery man protecting Kate, identified as Mr. Smith, being threatened by Maddox to give up the information he is using to blackmail them.