Night Train for Inverness

7-year old Ted has diabetes. When he leaves the hospital, the doctor tells his mother Ann not to forget the insulin injections twice a day, which for Ted is a matter of life and death. At the same time as Ted leaves hospital, his father Roy leaves prison. During his six months in jail Roy has written a letter every week to his wife, but his mother-in-law has torn them up, to prevent her daughter from reading them. She has also convinced Ann to divorce. Roy rents a room in London, and then goes to Ann's house to visit her and their son. The mother-in-law tells him to stay away, because Ann and Ted don't want to see him anymore. In his despair Roy involves an old sweetheart in a plan to kidnap Ted. If she accompany them on the night train to Inverness, they will be perceived as a family, and thereby not evoke any suspicions. He doesn't know that Ted has diabetes and needs his injections. The police soon find out that Roy has kidnapped Ted, but they don't know where they have gone. Ann, the doctor and the chief inspector wait nervously at Scotland Yard for information, while the night hours are passing by. Ted must soon be found and get insulin, otherwise he will die.