At the end of her first unsuccessful season out in society, Lady Georgiana has all but given up on attracting a suitable man - until she receives an invitation to a masked Halloween ball at Broxley Manor. Georgie is uncertain why she was invited, until she learns that the royal family intends to marry her off to a foreign prince, one reputed to be mad.

Lady Emily Hardcastle is an eccentric widow with a secret past. Florence Armstrong, her maid and confidante, is an expert in martial arts. The year is 1908 and they've just moved from London to the country, hoping for a quiet life. But it is not long before Lady Hardcastle is forced out of her self-imposed retirement. There's a dead body in the woods, and the police are on the wrong scent. Lady Hardcastle makes some enquiries of her own, and it seems she knows a surprising amount about crime investigation...

Eleanor Trewynn is a widow of some years living in Port Mabyn, a small fishing village in Cornwall, England. In her younger days, she traveled the exotic parts of the world with her husband. These days, she's retired and founded the local charity shop. Her niece, Megan Pencarrow, transferred nearby and was recently promoted to the rank of Detective Sergeant.

Selchester Castle in 1953 sits quiet and near-empty, its corridors echoing with glories of the past. Or so it seems to intelligence officer Hugo Hawksworth, wounded on a secret mission and now reluctantly assuming an altogether less perilous role at Selchester.

It's Christmas 1909, and for once Lady Hardcastle - respectable gentlewoman, amateur spy - and her lady's maid, Florence Armstrong, are setting sleuthing aside. They are invited to the festivities up at The Grange, as guests of Sir Hector and Lady Farley-Stroud. But barely have corks been popped and parlour games played when a mysterious crime comes to light.