The wages of virtue

Sir Montague Merline and his platoon get into a bloody combat in Africa and they are all massacred except for one man. Since her husband is presumed dead, Lady Merline remarries, but Montague emerges a couple of years later in some African village, with no memory. After finding out about his wife's new life, he decides not to ruin her happiness and goes off to join French Foreign Legion. The descriptions of Legion garrison life closely match those contained in the autobiographical In the Foreign Legion by ex-legionnaire Edwin Rosen.