During the first series of "Life on Mars", the character was a Woman Police Constable serving in uniform. Early in the second series, DCI Gene Hunt allows her to join CID as Woman Detective Constable. Throughout both series, Cartwright helps the programme's protagonist, Sam Tyler adjust to life in the 1970s. A degree of attraction is displayed between the two characters, lending a distinct sexual tension. Cartwright is the only person in 1973 who Sam tells that he has travelled back in time, and she treats him sympathetically, believing that he is suffering from severe concussion after being hit by a car. During the of series one, when Sam climbs onto the police station roof, considering suicide, Cartwright convinces him not to jump.