When an assassination attempt is made on Frank's life, Danny goes on a hunt to track down the shooter and find out if the attack was random or by someone with a vendetta against the Commissioner.

When a knife-wielding attacker dressed as Baron Samedi, the Spirit of Death, stabs a man in costume on Halloween, Danny enters the world of voodoo. Meanwhile, DCPI Garrett opens up to Frank about a dark secret, and Erin and Nicky take Jack and Sean trick-or-treating.

When an officer is accused of using excessive force on a suspect, Frank finds his department under scrutiny from the community and the mayor. Meanwhile, Danny and Baez investigate the murder of a Wall Street securities trader who was deep in debt due to a gambling addition.