CSI Director Catherine Willows becomes ill as ease when a young woman, whom the veteran investigator once helped convict as a juvenile, resurfaces as a suspect in a current murder case. Meanwhile, DNA testing finally brings forth a new lead in the cold-case murder of Catherine's friend.

John Doggett returns and enlists Mulder's help to investigate animalistic murders occurring in Texas. Meanwhile, a now very pregnant Scully tries to mend a rift with her estranged brother, Charlie, while on bedrest at home.

Troy Harrison heads to the West Coast to take a job with the Los Santos Police Department, and he soon befriends two eager young officers. As the three friends rise the LSPD ranks, they must contend with crime, politics, and an unlikely trio of thieves enmeshed in their own pursuit of great fortune.