In 1876, on the eve of the Centennial Exposition in Philadelphia, twenty-year-old Vesper Holly and her friends clash yet again with the archfiend Dr. Helvitius, whose evil schemes plunge them into danger in the wild Pennsylvania countryside.
- ISBN10 0525445641
- ISBN13 9780525445647
- Publish Date 19 April 1990
- Publish Status Out of Print
- Out of Print 14 June 2021
- Publish Country US
- Imprint Penguin Books Ltd
- Format Hardcover
- Language English