Richard Guise follows a unique 450-mile route across England on foot and on his trusty bike Tetley. His guide is the wiggly line that divides rivers flowing west from those flowing east, a choice that takes him over rolling downlands, along windy ridges, through remote villages, across ancient battlefields, past abandoned airfields and even -- surprisingly -- by boat through a network of canal tunnels that echo to the sound of cannon fire. Accompanying or accommodating him on parts of this serendipitous journey are an array of locals with their own stories to tell: the quail-raising smallholder, the bumptious yachtsman, cake fans, ferret fanciers, re-writers of history and more. The route itself turns out to have historical significance and Guise roots out odd tales of passion and heroism, vision and fear, drunkenness, conceit, deceit and murder.