Kristy and the Mystery Train

Derek Masters, child star and friend of the BSC, is about to board a special "mystery train" publicizing his latest movie...and he wants a bunch of his Stoneybrook friends, including three baby-sitters, to join him!
It sounds like a blast, but problems appear before the train even leaves the station. Someone seems determined to ruin the trip - no matter what. Good thing the BSC is on the case, because this is turning into one dangerous ride!