A. F Steadman

Thirteen-year-old Skandar Smith has always wanted to be a Unicorn rider, but when the mysterious Weaver steals the most powerful unicorn in the world, Skandar must face sky battles, ancient secrets, and bloodthirsty unicorns in order to save his island.

To survive their third year of training, Skandar and his friends must complete a series of terrifying trials across the Island's elemental zones. Friendships, allegiances, and rider-unicorn bonds will be pushed to the limit--only the strongest will make it. Meanwhile, Skandar's sister, Kenna, has finally reached the Eyrie. But with a forged bond to a wild unicorn, she is alienated and alone. And when a terrible discovery puts the future of the Island...

"As Skandar and his friends begin their fourth year at the Eyrie, the Island's unicorns are struck by a terrible curse that threatens to change everything. Between a Commodore determined to eliminate the spirit element for good and a sister hellbent on revenge, nowhere is safe for Skandar. As more unicorns are affected by the curse, the clock is ticking for Skandar and his quartet, who find themselves racing for their lives. Can they stop the curse...