As Skandar and his friends begin their fourth year at the Eyrie, a chilling curse infects the Island's unicorns. Between a Commodore determined to eliminate the spirit element for good, and a sister hellbent on revenge, nowhere is safe for Skandar. As more and 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 in its tracks before the Island is lost for ever?