Brighton, 1920. 

Clara Fitzgerald is trying to earn a little respect as the first female private detective in Brighton when Mrs Wilton turns up on her doorstep one snowy day. Struggling to get by since the war, Mrs Wilton has been convinced by an unscrupulous clairvoyant that her dead husband is trying to make contact via strange riddles that supposedly lead to hidden treasure. Clara is quickly on the case to prove the notorious clairvoyant, Mrs Greengage, is nothing more than a scam artist extorting money from Mrs Wilton. 

But after an unpleasant seance, Mrs Greengage is found with a bullet in her chest, and Clara is rapidly a suspect as one of the last people to see her alive. There is no option but to unravel the mystery for herself, taking on the biggest case of her life, much to the consternation of the local police inspector. 

Soon Clara is discovering Mrs Greengage's dark past, her involvement in a previous murder case and her husband's strange talents. Why won't Mr Greengage leave his house? Why was Mrs Greengage's sherry laced with strychnine when she was shot to death? And just who is the man stalking Clara? 

Helped by her brother Tommy, a cripple since the Great War, and portrait photographer Oliver Bankes, who takes crime scene pictures for the police in his spare time, Clara sets out to prove who the real killer is. But little does she realise how emotional challenging discovering the truth will be.