A fire in an abandoned mill that kills several Latino squatters and a firefighter causes political fallout for Tommy. Colin begins drinking heavily because of a love triangle. Declan's investigation bears fruit and is expanded.

Declan's investigation triggers alarms among the corrupt politicians so Tommy tries to finesse information from the investigation. Rose receives a diagnosis and shares the truth with Ellen. Michael and Colin begin to clash as they help Freddie plan a robbery.

Tommy's plan to extricate himself from political entanglements hits a snag when Speaker Danatello seeks his help passing the budget. Declan learns more about Tommy's involvement in the Waterfront Project and connects Tommy to Nozzoli. Michael's jealousy over his mother's attachment to Colin adds fuel to his paranoia about Colin and Kath.

Michael returns to Kath but she and Colin begin to worry as the FBI fuels Michael's suspicions about their relationship. Eileen is confined to bed rest for the duration of her pregnancy. Tommy seeks Michael's assistance as Declan begins to zero his investigation in on the Waterfront Project.

Tommy becomes heir apparent for Speaker when Donatello's condition worsens; Freddie maneuvers to get on Tommy's good side; with the mob, the state police, and feds after him, Michael's obsession with Colin puts everyone in jeopardy.