Mystery Train is a Nancy Drew and Hardy Boys Supermystery crossover novel. It was published in 1990.[1]
Nancy, Frank, Joe, and Bess 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.
The 13th installment in the Nancy Drew point-and-click adventure game series by Her Interactive, named , is loosely based on the novel.