Deep in the lair at Blue Mountain, Naytin the dragon safely guards the Indigo Star. The jewel's magic has always protected the indigo herd. Until now.
The evil Shifter has captured the Indigo Star and gained control over the band of unicorns. As the Shifter's darkness creeps through Balinor, now not even the unicorns are safe.

The indigo unicorns are fading, and so are their spirits. Princess Arianna and the Sunchaser must reclaim the jewel--before the unicorns slip into the shadows of the Shifter.