Skandar and his sister Kenna are finally both at the Eyrie, but tensions are high.

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 Kenna's forged bond to a wild unicorn has left her alienated and alone. And when a terrible discovery puts the future of the Island in peril, all fingers point in one direction.

As dark forces assemble, Skandar must decide how far is he willing to go - for Kenna, and for the Eyrie.