Nolan is given some life-changing news and invites Grace over for a homecooked meal in his newly remodeled kitchen. Meanwhile, each unit is tasked with following up on dormant cases in the hopes they can uncover new leads.

When a new designer drug hits LA streets, it turns users into “zombies,” and Officer Nolan and the team have a Halloween they won’t soon forget. Back at home, Lucy questions whether her apartment building might be haunted.

Officer John Nolan is forced to spend a week in solitary confinement in a quiet border town with a young local officer who is in need of some training. Meanwhile, Sergeant Bradford and Officer Chen discover that looks are deceiving and go undercover together in a possible drug trafficking case.

The team comes together to celebrate John and Bailey’s wedding; meanwhile, Celina discovers a discrepancy in her case, leading to a new discovery. Elsewhere, Lucy and Tim’s relationship is put to the test.

The team helps Skip Tracer Randy when his new love interest is kidnapped. Meanwhile, Angela and Nyla enlist their moms to help catch a con artist, and Wesley is threatened to drop a case.