The Essex Serpent, Sarah Perry’s second novel and the prize-winning, bestselling book that made her name, merely flirted with the motifs and machinery of the gothic. With its perspicacious heroine, a seemingly impossible aquatic creature glimpsed in dark water and rural landscape of the bleakest and most minatory sort, it was content just to hint at the existence of the supernatural before drawing back warily into realism. The follow-up to that immensely successful project, Melmoth chooses not to flinch away in such a fashion but rather rushes, full tilt and without apology, towards the uncanny.

We begin in 21st-century Prague, where a glum, solitary Englishwoman named Helen Franklin is embarking on a lonely middle age. Her apparently (deceptively?) unremarkable nature is given literal form: ‘neither short nor tall, her hair neither dark nor fair’, she sits at ‘a small plain desk, [on] a