Roberta, Peter, and Phyllis used to live in London. But their father, who worked at the Foreign Office, was accused of spying-and now he's in prison. So they've moved with their mother to the Yorkshire countryside, to a house near the railway called the Three Chimneys.
They may have much less money than they did before, but the siblings still have a great deal of adventures, and soon they make plenty of new friends: the "Old Gentleman," who takes the 9:15 train, plus the station porter, the stationmaster, an engineer, a fireman, and a mysterious Russian man who steps off the tracks with a remarkable story to tell.
Before long, the Old Gentleman will do something very special to help his young chums-and the children will have their own chance to be heroes as well...
