When two people with no obvious connection receive similar notes and are then killed by targeted bombs in 24 hours, Carter and Lee have little to go on as they scramble to identify the bomber before he strikes again.
Lee's sister puts her life on the line when she tips him to the Quantou gang's trafficking of women into Los Angeles, which sends Lee off on his own to dig up inside information about the gang.
Lee and Carter go undercover as teachers at at prep-school to solve murders linked to the death of an undercover narc who tried to stop the sale of a new designer drug called raxxa.
After thwarting an armored truck robbery on a busy highway, Detectives Carter and Lee discover it may have been a dry run for a bigger heist but disagree who the suspects are.
A smitten Carter asks Lee to be his wingman with a beautiful witness, Nina, who they are protecting before she testifies against her former menacing boss.
Detectives Carter and Lee hunt an escaped prisoner searching for his estranged wife and daughter who are in witness protection. When the pair goes missing, the Detectives must find how their location was compromised.
Captain Cole enlists the help of Detectives Carter and Lee as she fears the return of a serial killer when a young woman's recent disappearance at a hotel believed to be haunted mirrors a series of chilling unsolved cases from five years ago.
When seemingly upstanding members of society are being publicly humiliated by a mystery man, Detectives Carter and Lee search for someone targeting powerful people with something to hide.
When a meeting of rival Los Angeles gang lords is orchestrated by the Quantou gang, Carter and Lee must infiltrate it to find Lee's sister Kim and save her from going further with the Quantou in the series finale.
