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

A new murder in Buell ignites Steve's determination as he intensifies his suspicions of Grace and Del; Del persists in his investigation of the Pittsburgh bombing while also becoming further entangled in the Brotherhood.

Del invites Vic for a weekend of male bonding at his cabin; Grace confronts Sue head-on during the District Attorney debate; the town of Buell is shaken by another murder of a resident, prompting Steve's suspicions about Grace to intensify.

Del and Vic grow closer during their weekend in Buell; Lee grows more suspicious of her law firm; a job prospect presents itself to Grace.

Del feels pressure surrounding the Brotherhood as he looks into Vic's disappearance; Lee and Isaac argue about her feelings.

Del involves Angela in his covert scheme; Grace receives a tempting job offer yet worries over Billy's behaviour; Lee and Isaac hold a memorial service for their father.