After Raglan James, the Body Thief, steals Lestat’s vampire body, Lestat (in Raglan James’s mortal body) begins suffering pneumonia. In a hospital, he is cared for by Gretchen, a Roman Catholic nun, who is experiencing a crisis of faith. She takes him home with her, to better care for him. He tells her his life story and promises to share his life with her. After a night of passionate intimacy, which allows Lestat to experience sexual pleasure for the first time in two centuries, he decides that he needs to find his vampire body, while Gretchen decides that she wants to return to the religious life in a South American mission.
Gretchen appears in The Tale of the Body Thief (1992). For more perspectives on her character, read the Alphabettery entries Lestat de Lioncourt and Raglan James.