Bridge at War by Trevor Hopkins - Free

A prequel to New Bridge to Lyndesfarne, Bridge at War is set in 1946, immediately after the end of the Second World War. The story follows three young men - Tom, Alistair and Bram - who were comrades in the Army during the war. Bram gently introduces the world of Lyndesfarne to the others, and engineers their recruitment into the Guardians, one of the secretive organisations whose purpose is to protect the crossing to Lyndesfarne.