Kate decides that she can make more of a contribution as a detective than as a captain. Gates doesn't like that and blames it on Castle. A murder pulls Kate into a much larger investigation.
Teresa Wyler was murdered by her husband who's been in prison for fifteen years. There's no reason for Rick and Kate to get involved, is there?
Kate is forced to take a vacation to relax. But some friends show up with a problem and off Kate, Rick and Alexis go.