On Globik’s mission again, the Travel Sisters have to find Dannebrog, which has disappeared from the National Art Gallery. With the help of Erik and Erika, twins from the school, the sisters search throughout Denmark. On their way, Sophie and Stephie fight Vikings, escape from a medieval castle, and meet a mermaid. But will their adventures lead them to the missing Dannebrog? Do the girls even know what they’re looking for?
