Susanna Calkins, former housemaid turned printer's apprentice, Lucy Campion is out peddling her pamphlets when she encounters what she thinks is a apparition.
It turns out to be a woman clad in a bloodstained nightdress and barely able to speak. When questioned by Lucy the woman is almost incoherent and has no memory of who she is or why she is wandering around the area.
Lucy notices cuts on her hands and bruises on her arms as if she had been bound. Without hesitation, Lucy brings the woman to a local physician, who at first claims he doesn't treat charity cases, but Dr, Larimer remembers his Hippocratic Oath and takes her in.
Before long it appears the woman is the daughter of a nobleman and Dr. Larimer asks Lucy to stay and be her caregiver while she recovers. The woman turns out to be Octavia Belasysse, the daughter of a lord and the sister of a member of parliament. Dr. Larimer's assistant Mr. Sheridan believes Octavia had been pronounced death eight months ago and buried in a family plot.
Where has Octavia been for the past eight months and why is she so terrified of her family? Adding to her loss of memory is the "falling" illness she has (now know as epilepsy).
Octavia slowly begins to regain her memory, but there are large gaps and Lucy knows there are things she is holding back. Along with Constable Duncan, Lucy begins to investigate and her discovery leads her to a famous location.
Lucy discovers some dangerous facts that might cause Octavia more harm, but along with Constable Duncan they aim to keep her safe.
An excellent adventure from a period of time where not many mystery novels are set. I thoroughly enjoyed A Death Along the River Fleet.