It's the first day on the job for Langston (Laurence Fishburne) as the newest CSI team member. While initially thinking his first day would include only a simple burglary call, he and the team are soon called to solve an arson and homicide case. The victim, a local gym owner, was found burned in the ruble of his home. CSIs find he was murdered before the fire was started and begin to uncover financial as well as marital problems that give cause for a number of people to want him dead. Investigators are puzzled by what started the fire and Langston is instrumental in figuring out the unusual detonating device which accompanied by video surveillance from the gym leads CSIs to the victim's housing contractor; who committed the murder because he was in love with the victim's wife. What was a simple burglary touches a nerve with Langston as a young boy is forced to help police catch his mother for the crime. With Grissom's departure, the team is trying to adjust to life without him and Catherine takes the step she feels will allow her team to begin moving on.