In this fourth mystery about 12-year-old Maisie, the young detective must solve a crime for her friend Professor Tobin. The professor travelled all over the world collecting strange and wonderful objects, and the British Museum is opening a special room to house his collection. But before the professor's donation, a thief steals a valuable Amazonian tribal mask! With just a single feather left behind, Maisie doesn't have much to go on, but the stakes in her newest case are higher than ever. Can't get enough of Maisie's mysteries? Look for The Case of the Stolen Sixpence, The Case of the Vanishing Emerald, and The Case of the Phantom Cat!