Early in the morning of the 22nd of June, 1859, the body of Joanna Franks was found floating at Duke’s Cut along the Oxford Canal – an event which led to the trial and hanging of two suspected murderers.

A hundred and thirty years later Chief Inspector Morse is bedbound and recovering from a perforated ulcer at Oxford’s John Radcliffe Hospital when he is handed an old book to read, one that recounts the trial of a murder aboard the Barbara Bray canal boat: the murder of Joanna Franks. Investigating the account of the trial, Morse begins to question whether the two men hanged were truly guilty and sets out to prove his suspicions from the confines of his hospital bed . . .