"Thoroughly Modern Millie" is a musical set in the 1920s that follows the story of a young woman named Millie Dillmount. She moves to New York City with dreams of a modern life, seeking independence and adventure. The show explores themes of ambition, love, and the changing roles of women during this vibrant era. The musical features a lively score and incorporates elements of jazz and flapper culture. It highlights the contrast between traditional values and the new, modern lifestyle. Characters like Miss Dorothy and Jimmy Smith play significant roles in Millie's journey, adding depth to her experiences in the bustling city.