Three generations of the Grant family live and work on the Severn Valley branch of the Great Western Railway, from the Victorian era to the Second World War.

Split into three different stories, 'The Permanent Way' tells the construction of the line in the 1860s, 'Clear Ahead' shows the line in its Edwardian heyday in 1906 and 'Fire on the Line', set in 1939, shows how the outbreak of the Second World War affected both the family and the railway.—Anonymous