It is 1923, and Daisy Dalrymple is on her way to Scotland via the Flying Scotsman, on which she meets an old schoolfellow, Anne Breton. Anne and all her relatives are en route to the deathbed of the family scion and notorious miser, Alistair McGowan, whose will leaves his entire fortune to his brother Albert. The rest of the family is determined to change his mind. Daisy, meanwhile, has her hands full taking care of Detective Inspector Alec Fletcher's daughter Belinda, who has stowed away aboard the train. Daisy barely has time to notice the family feud taking place all around heruntil Albert McGowan is found murdered on the train and Daisy is surrounded by suspects.