In 1905, John Vanbrugh, an ambitious young architect, receives an invitation from the Duchess of marl-borough, the American-born Consuelo Vanderbilt, to visit Blenheim Palace and help her with renovations. Vanburgh joins a weekend house party that includes a young Winston Churchill and John Singer Sargent, who has been hired to paint a family portrait. Right away Vanburgh learns that Blenheim has many dark secrets. The mystery grows as a young housemaid is found strangled in the courtyard. From there, events spin out of control, with Vanbrugh soon realising that he too has fallen victim to Blenheim's cursed history.