Book 1

Song Quest

by Katherine Roberts

Published 2 September 1999
When a mainlander ship is wrecked and the beautiful Merlee are heard crying across the waves, the lives of three novice Singers are changed forever. Raille, her friend Freen, and the rebellious Kherron find themselves involved in an epic battle to save their entire world.

Book 2

The Crystal Mask

by Katherine Roberts

Published 1 August 2001
Shaiala scrambled down the canyon floor...The sight beyond brought her to a halt. Nearly a hundred exhausted, frightened Centaur foals...hobbled and taunted by Two Hoofs. The second book in the Echorium Sequence and a stunning sequel to SONGQUEST, winner of the Branford Boase Award. A wild girl, a horselord prince, half-creatures, the rumoured return of the dreaded Khiz priest, and an awesome challenge to the power of the Singers make the Crystal Mask a breathtaking new adventure which started so brilliantly with the award-winning SONGQUEST. In a world where the slightest whisper can bring down an avalanche, black crystal is destroying the Second Singer's power. It's a race against time, and their own fears, if Renn, the novice Singer and Shaiala with her raw physical strength are to conquer the evil power that has enslaved Half Creatures and Two-Hoof children - a power that can bend minds and steal memory.

Book 3

Dark Quetzal

by Katherine Roberts

Published 1 March 2003
When the Singer Rialle disappears in suspicious circumstances and a pirate force kidnaps a young novice, the Singers suspect the return of their old enemy. Frazhin the evil sorcerer has returned and is hiding deep in the Quetzal forest. From here, he plans his revenge on the Singers of the Echorium, to obliterate them from the memories of all, both humans and half-creatures, replacing them with a history and dynasty of his own creation. He has already enslaved the half-creatures to do his bidding and has discovered the whereabouts of his dark Princess and the existence of a daughter, Kyarra, both hidden on the Isle of Echoes. As soon as his pirates return he will have everything within his grasp. But one of his half-creatures breaks free, a handsome half-boy, half-bird known as the Dark Quetzal. He files across the Seas to join forces with the Singers and together they battle to save the world from the power of darkness, once and for all. Unexpected help comes from some wonderful old friends of The Echorium Sequence - and Kyarra, a brave and spirited girl who in the end must face the dark forces led by her own father.
Dark Quetzal is set 11 years after the events of Crystal Mask and is the final thrilling adventure in The Echorium Sequence, the epic saga that begun with the award-winning Song Quest.