-Kate Beckett is out of work. After being fired from the FBI she can't get her job back with the NYPD due to a hiring freeze.
-Emma Riggs wakes up to find her boyfriend, Angelo stabbed to death in her apartment. She runs from the police when she arrives, takes hostages in a dentist office and refuses to talk to anyone but Richard Castle.
-Castle is called in to talk to Emma who wants him to prove her innocence. Castle sets out to prove she's been framed. When one of the hostages tries to take the gun, Castle is shot in his bullet proof vest.
-Turns out Angelo was trying to track down Emma's birth parents. When he went to talk to her rich, powerful, biological father, he found the son-in-law instead who killed Angelo so that he and his wife wouldn't have to share her trust fund money.
-Emma's birth father, Aaron Stokes is so grateful to Captain Gates for her help on the case, he calls his friend the Police Commissioner and has Beckett reinstated per Gates request.
-Gates says Castle can also return as a police consultant as long as he and Beckett keep their relationship professional at work. It's her engagement present to them both.