As the team investigate the disappearance of a prominent Boston attorney, secrets of the man's past are revealed.
A pregnant convict falls into the hands of two unscrupulous human traffickers, so Givens and Gutterson mount a rescue operation. Meanwhile, a love triangle forms between Givens, his ex-wife Winona and her estranged husband Gary. Elsewhere, criminal matriarch Mags Bennett begins to consolidate her power base.
Brennan's past returns to haunt her when notorious serial killer Howard Epps, a man she put behind bars, escapes and vows the ultimate revenge against her.
A notorious serial killer, who Brennan helped put behind bars, plays a deadly game with the forensic scientist.
Castle and Beckett investigate the murder of a man whose body was found in a family's house on their return from holiday. At the same time, Castle is elected as one of New York's 10 most eligible bachelors.