Holmes and Watson come face-to-face with Moriarty when their adversary is brought in as a consultant on a kidnapping case. Meanwhile, Detective Bell continues his struggle on the road to recovery.
As Peter and the city of Chicago prepare for a possible riot, Frank Prady and Alicia face each other in an important debate.
Danny faces a moral dilemma when he's involved with a gun amnesty scheme but suspects a good samaritan may be linked to a robbery.