Calleigh and Ryan are called to a house to investigate a man’s death, and they find his body in the attic. But when someone enters the house and locks them up in the attic, the lives of the CSI’s are in jeopardy as a fire breaks out inside the house. They barely make it out of the house, however, the danger isn’t over yet as Calleigh has a late reaction to all the smoke she inhaled. She is immediately driven to the hospital, where Alexx and her team tries to help her.