Detective Carmen "Nova" Riley was a undercover police detective who formerly worked with the Narcotics Division, assigned by Bill Brewster to infiltrate the Marcy Killers/Corporation. She continued to work that undercover assignment, under the supervision of Ayanna Bell from the Organized Crime Control Bureau. Following the suspicious murder of crime lord Preston Webb, she resigned from the NYPD and moved back to her hometown with her brother.
While undercover with the Marcy Killers, Riley started a relationship with a woman named Penda. After Penda was killed in a drive by shooting, Bell and Jet went to talk to her about what happened that night. However, they later found out that she was an undercover detective working for Brewster, which angered Bell. (OC: "New World Order")
Riley was distraught after Penda's death and told Brewster that she is going to go to her funeral. Brewster told her that he forbids her to go and Riley handed him her gun and badge and resigned. At Penda's church, Bell persuaded Riley, using the story of what happened to Gina Cappelletti, to come back to the force and help them find Penda's killers, which Riley agreed to do. (OC: "The Outlaw Eddie Wagner")
Riley was rewarded by the other members of the Marcy Corporation by giving her a promotion to Vice President, making her a member of the senior management. She also lets Bell know that at the meeting where she got her promotion was Preston Webb and his mentor Congressman Leon Kilbride (aka Mr. Taylor), who has been showing an interest in Ayanna as a possible new recruit. (OC: "Ashes To Ashes")
After discovering that her brother, Derrick, was going to start a charity sponsored by Webb and Cassandra at the church, Nova approached Derrick and revealed to Derrick that she was an undercover detective investigating Webb. Derrick told her that their father, Tobias, would not have liked this because he was a police officer killed in the line of duty. (OC: "Can't Knock The Hustle")
After Preston was found murdered and his wife Cassandra was arrested for his murder despite not committing it, Carmen handed in her badge and gun, departed the Organized Crime Control Bureau and left New York for good, with indications that Carmen murdered Preston herself, which could ultimately never be proven despite the charges against Cassandra eventually being dropped, resulting in Preston's murder remaining unsolved. (OC: "Friend Or Foe")
- Riley is the only main character on Law & Order: Organized Crime that hasn't starred on Law & Order: Special Victims Unit.
- Riley is the first main character on OC to have previously starred as a recurring character.
- Riley is the second main character in Law & Order: Organized Crime and the fifth in the Law & Order franchise who is both a member of the LGBTQIA+ community as well as person of color after George Huang, Arleen Gonzales, Katriona Tamin, and Ayanna Bell. She is the sixth LGBTQIA+ main character after Law & Order character Serena Southerlyn.
- Riley is the only main character on Law & Order: Organized Crime to appear in only one season. Alongside that, she is the shortest serving main character on the series.
- Carmen is the fourth shortest serving main character in the franchise on a show with more than one season, with Richard and Angela Wheatley being fifth, Kim Greylek being third, Nola Falacci being second and Nick Falco being first.
- Law & Order: Organized Crime (1 season, 16 episodes):
- Season 2: "The Man With No Identity" • "New World Order" • "The Outlaw Eddie Wagner" • "For A Few Leke More" • "Unforgivable" • "High Planes Grifter" • "Ashes To Ashes" • "Nemesis" • "As Iago Is To Othello" • "...Wheatley Is To Stabler" • "Takeover" • "Guns & Roses" • "Can't Knock The Hustle" • "Dead Presidents" • "Streets Is Watching" • "Friend Or Foe"