One rainy night, a canal worker stumbles across the strangled body of Mary Lampson in a stable near Lock 14.
The dead woman's husband seems unmoved by her death and is curt and unhelpful when Maigret interviews him aboard his yacht.
But gradually Maigret is able to piece together their story - a sordid tale of whisky-fuelled orgies and nomadic life on the canals.
Can the answer to this crime be found aboard the yacht? Or is the murderer among the bargees, carters and lock-keepers who work the canal?
In Lock 14, Simenon plunges Maigret into the unfamiliar canal world of shabby bars and shadowy towpaths, drawing together the strands of a tragic case of lost identity.