A Prince of the Captivity - John Buchan - Bog

Adam Melfort marries beautiful but mindless socialite who cannot return his love for her. When she forges her wealthy uncle''s signature on a cheque, he takes the blame to save her family''s name, and is jailed, losing his army commission in the process. Melfort allows her to divorce him so that she can remarry someone of more similar mind. After being released from gaol during World War One, he is recruited as an undercover agent behind enemy lines in Belgium...