Surrey, England, 1934: when celebrated portrait painter Lucien Vidal is found dead in the locked studio of Blackthorn House — his latest canvas still on the easel, his laudanum tampered with, and a rival artist's cufflink lying conspicuously near the body — a brilliant Belgian detective unravels a web of old scandal and cold hatred buried beneath fresh paint; the key lies not in who is visible in the portrait, but in who has been painted over — a hidden image beneath the surface canvas revealing a woman's throat encircled by gloved fingers, an earlier truth that Lady Frances Welby had desperate reason to destroy before it could speak; inspired by the golden age of country house crime while remaining entirely fictional, The Portrait at Blackthorn House is an original Golden Age–style mystery about obsession, buried secrets, and the treachery of appearances.