En una pequeña ciudad del cinturón de óxido en el suroeste de Pensilvania, el jefe de policía Del Harris investiga después de que un cadáver aparece en una fábrica de acero abandonada.

La investigación de Harris continúa. Isaac abandona la ciudad. Billy y Lee se reencuentran mientras Buell celebra un casamiento a la fuerza.

Grace solicita ayuda en su esfuerzo por sindicalizar a las modistas. El sheriff recibe un aviso anónimo sobre el asesinato en la acería.

Isaac se hace amigo de alguien que le enseña las reglas del camino. El sheriff busca pruebas en el tráiler de Billy y Grace. Billy le cuenta a Lee lo que pasó en la acería.

Harris corre contra reloj en su búsqueda del testigo anónimo. Lee busca asesoramiento profesional sobre a quién proteger. El antiguo socio de Harris en el Departamento de Policía de Pittsburgh lo visita.

Alejandro se entera de la historia de Lee con Billy. Isaac realiza su primer truco en solitario. Harris viaja de regreso a Pittsburgh con su antiguo socio para pagar una deuda.

Billy se busca la vida en prisión. Isaac se ve más solo que nunca. Grace planta cara a su jefe. La investigación del testigo anónimo se complica para Harris cuando un jugador del equipo de fútbol del instituto sufre una sobredosis.

Isaac is taken in by a kind stranger. Grace’s union drive is put to the test. Billy fires his public defender. Harris realizes what he has to do.

Harris finally finds the anonymous eyewitness. Lee decides not to return to New York. Billy is returned to the general prison population to face the consequences of his actions. The D.A. may be forced to drop the case. Season finale.

Four months after the shoot-out in West Virginia, Del has returned to the Pittsburgh P.D. while the folks in Buell try to get their lives back on track.

A new murder in Buell lights a fire in Steve as he doubles down on his suspicions of Grace and Del. Del continues to investigate the bombing in Pittsburgh while also becoming more enmeshed in the Brotherhood.

Del invites Vic out to his cabin for a male bonding weekend. Grace goes toe-to-toe with Sue at the District Attorney debate. The town of Buell is rocked by another murder of one of their own, while Steve’s suspicion of Grace grows.

Del and Vic grow closer during their weekend in Buell. Lee grows more suspicious of her law firm as her investigation leads her to surprising evidence. A job prospect presents itself to Grace, and Isaac and Russell bond after a harrowing experience. Steve’s suspicion of Grace and Del grows into an obsession.

Del feels pressure surrounding the Brotherhood as he looks into Vic's disappearance. Lee and Isaac argue about her feelings regarding her job. Isaac’s feelings are hurt when he crosses paths with someone from Russell’s life, while Billy's behavior grows more erratic and causes him to act out.

Angela is brought into Del's secret plan. Grace receives a promising job offer, but remains worried about Billy’s behavior. Lee and Isaac have a memorial service for their father.

Lee’s involvement in the Landwill case deepens. Isaac receives a surprise visit and Billy’s behavior ruins a dinner party. Del fears for Angela’s safety while Grace misses Del.

Billy has a new lease on life after finally confronting his past and makes strides to secure his future. Lee is in trouble as Rinna investigates the missing documents. Russell returns to Buell to find Isaac moving on. Angela and Del are wary of mysterious circumstances surrounding a death.

Cynthia becomes suspicious of everyone as she tries to figure out what happened to Vic. Angela and Del are surprised when they arrive at an urgent police call and things are not as they seem. Lee reconnects with Alejandro when she goes to New York to sign their divorce papers.

Fighting crippling pain, Del is determined to continue his investigation and turns to Steve for help. Billy leaves for basic training and finds comfort when he befriends a fellow traveler. The Landwill conflict comes to a head.