"The Undertaking of Hart and Mercy" (£9) by Megan Bannen feels like "You've Got Mail" crossed with a quirky Western-inspired fantasy setting. Hart, a marshall patrolling supernaturally dangerous territory, and Mercy, an undertaker trying to keep her family business open, rarely have a kind word for each other. What they don't realise is that they're each other's anonymous pen pals. When magical dangers threaten to encroach on their town, they'll grow closer — but the reveal of their true identities could spoil the bond that's been building through letters.