What do you get when you mix a rescue mission, a 50-year-old motorbike, an 11-year-old boy, and his weird, witchy grandma?

Zack Mosel’s parents are settling business in far-off Slovodnia, so Zack has no choice but to spend his summer with "Mag the Hag," his eccentric grandmother. But before the summer can get too boring, Zack finds out his parents have gone missing, and he and Mag take it into their own hands to unravel the mystery surrounding their disappearance. What follows is an adventure that will take Mag and Zack across Europe, facing wilderness, danger, new friends, enemies, and excitement—all while traveling on the seat of a pretty extraordinary motorbike.