When the 7-4 investigates a fatal fire at a hair salon, Killian and Morales turn to Dr. Ken Corley, a medical examiner with ties to Regina's past, and fire marshal Nicky Greenville for crucial insight. Also, Haywood announces a new policy without discussing it with Suarez, and Quinlan worries about Bentley's worsening nightmares.

When a body is found at the construction site of a new high-end housing development, the team races to find the killer amidst a contentious gentrification battle in the neighborhood. Also, Quinlan's mother, Ann-Marie, pays an unexpected visit.