Thora - half-mermaid, half-human - is off to the farthest faraway place on earth: Flinders Island. Flinders is the home of Cosmo, Thora's pet peacock. But when they find the wildlife sanctuary where he was born, all the peacocks have disappeared! Thora is suspicious. And when she gets a job helping out with Felicity, whose parents run a rubber dinosaur factory, the questions pile up. This is the most important voyage of Thora's life: a journey that features magical crystals and squidgy dinosaurs - and leads her to the biggest mystery of all ...