She was played by Barbara Stock.
Desire was a vampiress who had been prowling the dark streets of various towns before arriving in Los Angeles, in the guise of a nurse named Mona. She worked at the same hospital as the main character, David Balsiger, who worked as a coroner's assistant, and she came in physical contact with David at one point when she attacked him. After his encounter with the vampiress and learning more about her from an ex-communicated priest named Paul, David encounters Mona as he's driving down the street, and later drives Mona to her house.
Mona turned heel and began coming on to David, right before she headed upstairs to change. Mona slowly walked downstairs in a black gown and continued seducing David, who resists her villainous advances. At this point, Mona continues following him and cements her heel turn by revealing herself to David as the evil Desire when her vampire fangs elongate. Desire manages to trap David on a balcony, but when she leaps towards him, she falls to her death.
- Barbara Stock later gained more fame for her appearance on Seinfeld as the Scam Woman in Season Three's "The Subway." Her co-star, David Naughton, appeared two episodes earlier in "The Red Dot."