We Didn't Start the Fire

Plot:

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.