Summer holidays have begun and Simon is looking forward to spending a few weeks of rest and relaxation at his Aunt Abygale's place near the sea. A magical shimmering platelet, blinking in the morning sun under Simon's window, catches his immediate attention. Had he only been dreaming, or had somebody really been at his window last night? Together with his best friend Richie, he tries to learn the secret behind his mysterious find. Little could either of them know that they were holding the key to an incredible adventure. Things come thick and fast when the inscrutable dragon Grewels arrives in Aunt Aby's garden by night. Incredulous, the two boys listen to the tale of Asragur's prophecy and the legacy of the old dragon king. Should Simon and Richie really believe the incredible story told to them by their scaly guest? Curiosity gets the better of them and the two friends follow the dragon, embarking on a perilous journey into a foreign world.