Mystery Train
 Nancy, Frank and Joe are all on the trail of the Comstock Diamond Case, an unsolved theft case, that has worked its way to the interests of a team of "professionals", with a "missing" reward of $25,000. The first step in solving the crime is to recreate the trail of the culprit, boarding a train from Chicago to San Francisco. But the case turns deadly when a shadowy suspect starts to sabotage the train. It is up to the trio to find suspects, solve the case, and bring the real cold-hearted criminal to justice. They face, a kidnapper, a thief, and a saboteur.