The Chicago Druid and the Ugly Princess is a story that moves from a time of Irish folklore to modern-day Chicago. The mix of this mythological Irish background with contemporary American life is one of the novel's strengths and provides many instances of humour and contrast. It follows the adventures of Fionnuala, a beautiful princess transformed into the ugliest women imaginable by the druid Lochlain, before being sent into the future. In modern Chicago, she encounters madcap characters, such as the crafty Patience, who uses Fionnuala's powers to make money gambling, and implicates them in gang warfare. She is hunted down by the magical characters from her past, who are searching for the mythological Salmon of Knowledge. In between she is also targeted by the police as a suspect in a terrorist case, and is on a mission to regain her former beauty by finding her one true love. The tone moves from the seriousness of the prologue to something altogether quicker and more irreverent as the novel progresses, keeping the story modern and the reader interested.