Author of four previous well-regarded novels sometimes labelled as “women’s fiction,” Sally Hepworth branches out stylistically with “The Mother-in-Law.” Roughly alternating chapters in the first person present tense explore the rocky relationship between hesitant Lucy and her determined, principled mother-in-law Diana, ricocheting between flashbacks and the fraught current situation where Diana has been found dead. Hepworth is a lovely stylist and the individual scenes are evocative and nuanced, but the trappings of a suspense thriller – what really happened to Diana and what did the supporting cast of characters really do? – make for a reading experience that never gets beyond vignettes. Towards the end I found myself whispering that the latest plot twists weren’t credible, and even the two main characters lost power as the plot buckled under their feet. Final result: much to recommend here, and a likeable read, but somehow sapped of depth.