After the excitement of his adventures aboard the Highland Falcon Thief, Harrison Beck can’t wait for the opportunity to go on another amazing train journey. So when his Uncle Nat invites him aboard the California Comet, the iconic three-day train journey from Chicago to San Francisco, he leaps at the chance to travel. But when the daughter of billionaire entrepreneur August Reza goes missing en route, Hal finds himself with another mystery to solve. Can he uncover the kidnapper before the journey’s end?