Retired archaeologist Judith Potts lives alone in a faded mansion in the peaceful town of Marlow, filling her time by setting crosswords for the local paper. During one of her regular wild swims in the Thames, Judith hears a gunshot coming from a neighbour's garden and believes a brutal murder has taken place.
A body is pulled from the water in episode 1 and in episode 2 there's an underwater camera that shows an object being pulled up from underwater by a magnet.
Minor character is a N**i memorabilia collector and has a secret room filled with N**i stuff. It's implied he subscribes to N**i beliefs but he doesn't use hate speech in this episode.