After Siloé and her half-brothers unexpectedly entered the Hexaworld, Nola learned a lot about her mother and the history of Pandorient. But the unanswered questions multiply when she discovers a strange key at home. What could it possibly open? To find out, Nola returns to Pandorient, only to learn of a disturbing disappearance. Are Nola, Igor and Andrea ready for an investigation that could turn life in Pandorient upside down? Will the secrets behind the strange key open a door to adventure or disaster? Find out in the fourth volume of this enchanting graphic novel series that will leave fantasy fans spellbound. Part of the The Music Box series.