As a train speeds over the Sankey Viaduct, the dead body of a man is
hurled into the canal below. Inspector Robert Colbeck and Sergeant
Victor Leeming take charge of their most complex and difficult case yet.
Hampered by the fact that the corpse has nothing on him to indicate his
identity, they are baffled until a young woman comes forward to explain
that the murder victim, Gaston Chabal, is an engineer, working on a
major rail link in France. As the case takes on an international
dimension, problems accumulate. The detectives wonder if the murder is
connected to a series of vicious attacks on the rail link that is being
built by British navvies under the direction of a British construction
engineer. Colbeck and Leeming have to survive personal danger,
resistance from the French government, broadsides from their
Superintendent, and many other setbacks before they solve the crime.