Agnes's drowning and Oliver's lasting blame
Susan Burling follows the mining engineer Oliver Ward through New Almaden, Leadville, Mexico and a failing Idaho canal venture, where she grows close to his assistant Frank Sargent. After their daughter Agnes drowns in the canal, Frank kills himself and Oliver withholds forgiveness, leaving a long, courteous estrangement. What happened between Susan and Frank, and whether her attention to him left Agnes unwatched, is Lyman's conjecture rather than a record the letters confirm.
