Sparkleap knows the stakes of the Stallion Trials, a yearly competition that tests the speed and agility of all two-year-old colts in his Herd. He will either be accepted into the Herd with celebration, exiled in shame, or slaughtered in cold blood. His bitterest enemy, the son of the Chief Stallion, is determined to win a place in their Herd and kill Sparkleap while he's at it. But when the headstrong colt turns up dead the morning of the Trials, Sparkleap begins to doubt the uneasy peace that has gripped the surrounding Herds for many seasons. When more and more horses are wounded by convenient accidents or turn up dead, Sparkleap knows there must be a saboteur in their midst. The only question is, what do they want? Will Sparkleap be able to stop them before it's too late?