All In (S09E24)

In the finale episode of the ninth season of CSI, a stash of missing chips from a long time closed down casino turns up in Vegas. A cast of quirky and suspicious characters cross the radar screen of our CSIs. This is a study of old time Vegas at its finest. When we meet Langston in this episode, he is volunteering in the ER, something that he doesn't tell anyone at work. By the end of the episode, Langston has to shoot and kill a murderer. This is the first time he takes a life in the line of duty. (CBS TV Network)