In Life on MarsEdit
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, leading 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 with sympathy, believing that he is suffering from severe concussion after being hit by a car. During the first episode of series one, when Sam climbs onto the police station roof, considering suicide, Cartwright convinces him not to jump.
Upon Sam first losing consciousness after being hit by a car which sent him back in time, he sees a fleeting image of a woman in a red dress running away from an attacker. The image is later revealed to be a childhood memory of Annie chasing after Sam's father, and being attacked by him.
No references are made to Annie's family in either the first or second series, apart from a mention of an unnamed nephew in "The Crash", which indicates that she has a brother or sister.
In Ashes to AshesEdit
Before the final episodes of Ashes to Ashes the reason for her absence and whereabouts have never been stated. During the course of Ashes to Ashes it is revealed that Sam and Annie married and were described as the "happiest couple ever seen" and had no children. In the finale, Keats mentions that there is no trace of Annie anywhere but it is revealed in the final episode that Gene Hunt, who helps souls of the police force pass on, ultimately helped both Sam and Annie move on.
Although it is never confirmed, it is strongly hinted that Annie was beaten to death by Vic Tyler in the real 1973 without Sam there to protect her.