After several of Bailey's patients die, she becomes the focus of a CDC investigation; Cristina teases Alex about his feelings for Jo; Owen continues to take care of Ethan while his parents remain in the hospital.
Castle is captured and forced to work with strangers to solve deranged puzzles and mind games, while Beckett and the 12th precinct must race against time to rescue Castle and catch a killer.
Pete and Violet go to a marriage counselor; Amelia gets some devastating news; Mason refuses to speak to Charlotte and Cooper; Violet suspects the sister of one of her patients.