Victoria, Australia, 1886...and 1903. Dark shadows fall across two golden summers, seventeen years apart. When beautiful Matilda Gregory, mistress of Summersby House, dies in mysterious circumstances her will brings to light an extraordinary deception - and a terrible wrong from the past. Summersby has a secret heiress, whose name is also Matilda Gregory, a strange, ethereal girl with an irrevocably broken memory.

Grieving Samuel Hackett seems somehow linked to his fiancee's death but a pact made with Barker, Summersby's scheming butler, proves effective in silencing tongues. The two men return the second Matilda to her inheritance - and set off a series of puzzling events. Two loyal servant girls, Aggie and Ida, gradually awaken to the sinister forces playing in Summersby's halls. Determined to aid the vulnerable heiress, the maids uncover strange vials, ghostly dogs, and letters from beyond the grave. These eerie messages hint of secrets from Summersby's past - and incidents destined for the future. Biddy MacBryde, a runaway kitchen maid not yet born in 1886, is separated from these events by a distance of half a generation. Yet Biddy's own path leads her towards Summersby, where in unwitting parallel with Aggie and Ida, she too uncovers a shocking truth about its heiress - and an even more startling legacy.