This novel is impossible to set chronologically into the Charmed series because it takes place in August, after Phoebe has dyed her hair blonde. Prue's death is in May, during the Season 3 finale, meaning theoretically the novel would have happened in the fourth season, had she not passed on. This is a prime example of how the authors were not always aware of the changes made in the show, and therefore could not plan very far ahead with their timelines and still hope to have things remain canonical.