It's 1895, Melbourne is in crisis, and Pearl and Vally Cole's father has suggested the unthinkable: it might be time to close the grandest bookshop in the world. When a ghostly visitor offers Pearl magic that could save her home, she seizes her chance. But her new friend is not what he seems, and the unstoppable magic in the palm of her hand comes at a terrible cost. Vally can see just one way to save Pearl before she is lost forever. He must call upon the sinister magician who nearly destroyed the Cole family two years ago.

But the Obscurosmith only performs the impossible for a price. Reunite with old friends, solve fiendish puzzles, and find five lost treasures from across the globe in this sweeping adventure that concludes the story of The Grandest Bookshop in the World.