When The Machine spits out five numbers, naming the Don of each of New York's crime families, Reese and Finch suspect Elias is planning to eliminate his competition. As Elias takes aim, someone close to Carter may pay the price.
Sherlock is reunited with "M." a British criminal who appears to have followed Sherlock to New York. Meanwhile, Joan has reservations about leaving Sherlock and taking on a new client.
Alicia learns more about her husband's fall from grace when she represents the wife of Peter's nemesis, Glenn Childs, in their divorce case. Also, Will gets cozy with his opposing counsel, Emily, during a wrongful death suit against caustic TV commentator Duke Rosco.
Danny becomes the lead hostage negotiator when a prime informant in a large drug case holds Erin at gunpoint inside the courtroom. Also, when Jamie disobeys his lieutenant's orders and gets suspended, Frank must decide a proper punishment.
Danny Reagan is accused of police brutality. Frank has to walk a fine line in the investigation and find the truth. Jamie meets a female doctor, and it makes Janko uneasy.
