Tessa Davies appeared first as the sister of Claire Davies (an assistant in the City Limit office who was preparing for her wedding). Later she was shown to be a barmaid at the pub in Tackleford where a number of characters hang out. Soon afterward, Rachel Dukakis-Monteforte started as another barmaid in the same pub, and they were later shown to be good friends. They soon enrolled as students at the University of Tackleford. When Rachel revived the long-dormant student newspaper of the university (in the process solving the mystery of what became of its former staff), Tessa assisted her.
Shortly after, the bar is destroyed and the two take a job as Interior Decorators for Len Pickering. Before they could be paid for the job, Amy Chilton went missing and was thought to have been murdered by her father. In order to clear his name and get their money, Rachel and Tessa enter an alternate dimension where Amy had been kidnapped and is now a celebrity to bring her back.
Later, Rachel was wanted by the police for manipulating a biker gang into shooting Shelley Winters , and so Tessa had to flee to Wales with her (where they then managed Space Owl's 2005 election campaign ). But they later returned to Tackleford as the evil leaders of the Little Sisters of Belial, where Tessa was known as Sister Nausicaa.
Tessa's whereabouts after Rachel's apparent death by bonfire where unknown for a long time, until she reappeared years later (together with Rachel!) within Mrs. Terry's secluded street of the forgotten.