In 1860, Inspector Jack Whicher of Scotland Yard is sent to rural Wiltshire to investigate the murder of the three-year-old boy Saville Kent, who was snatched from his bed at night and murdered.

Paddy Considine
as Inspector Whicher

Peter Capaldi
as Samuel Kent

Tom Georgeson
as Superintendent Foley

William Beck
as Dolly Williamson

Emma Fielding
as Mary Kent

Tim Pigott-Smith
as Commissioner Mayne

Kate O'Flynn
as Elizabeth Gough

Donald Sumpter
as Peter Edlin QC

Ben Miles
as Dr. Stapleton

Alexandra Roach
as Constance Kent