Hart is a marshal, tasked with patrolling the magical wilds of Tanria. It's an unforgiving job, and Hart's got nothing but time to ponder his loneliness. Mercy never has a moment to herself. She's been single-handedly keeping Birdsall & Son Undertakers afloat in defiance of sullen jerks like Hart, who seems to have a gift for showing up right when her patience is thinnest. After yet another exasperating run-in with Mercy, Hart finds himself penning a letter addressed simply to 'A Friend'. Much to his surprise, an anonymous letter comes back in return, and a tentative friendship is born. If only Hart knew he's been baring his soul to the person who infuriates him most - Mercy. As the dangers from Tanria grow closer, so do the unlikely correspondents. But can their blossoming romance survive the fated discovery that their pen pals are their worst nightmares - each other?