Billy Martin scores eight tickets to the Olympic Team Equestrian Trials in Las Vegas and the Crossbar show team is enraptured as they prepare to attend the prestigious competition.

World celebrated riders and their horses converge on the Thomas and Macintosh Center to vie for the championship title. As the Trials get under way, the teens are amazed to see Yoli Navarro, a familiar rival from home, enter the ring. She rides well enough to stop third on opening day and the kids cheer her on, hoping she can continue her winning streak.

Late that night, an old friend calls in a favor, and Becky Edwards goes to the show barn to braid several horses for the next day's classes. Piece working, she overhears two men talking just about sedation a horse. One voice is familiar, but at 1st she can't place it.

After the men leave, she checks out the horse, amazed to see it's Sirocco, a well-known and extremely graded Grand Prix competitor. The immense mare seems unaffected by any the men gave her, so Becky shrugs it off.

The next day, Dust storm is eliminated from the competition for steroid violations. Even as worse, Yoli is killed in a freak jumping disaster. Unhappy with the police finding of fact of accidental death and suspicious just about the quality of her riding performance, Billy buys the show tape of Yoli's round and the kids go back to their building to check it out. Horrified, they watch in slow motion as the tragedy repeats itself on their TV screen. They decide her death was no accident, and determined to find out what actually happened the kids go sleuthing.

They learn a side of showing they ne er knew existed and set a trap for several underworld mobsters. In the process, they besides reel in a cold-blooded killer they once called friend.