The Professor Wore Prussian Blue

In "The Professor Wore Prussian Blue," Daisy and Frederica Linden embark on a thrilling journey to rescue their father from a notorious gang of air pirates, with the help of Corporal Kent from the Royal Canadian Airborne Police. As their expedition takes a perilous turn after their airship is shot down, the Lindens must navigate the treacherous archipelago to locate the pirates' hideout and save their missing ward, Davey. This sixth installment in the Mysterious Devices series blends family ties, adventure, and a dash of romance in a captivating steampunk setting.