The Only One Left

No — it is a standalone novel, and you can read it without having read anything else by Riley Sager. His publisher lists no series for it. It appeared between The House Across the Lake (2022) and Middle of the Night (2024), but those are simply the books either side of it in his bibliography: they share no characters, no setting and no continuing storyline.

On the Maine coast, across two timelines. The present-day strand is 1983, when home health aide Kit McDeere arrives at Hope's End to care for Lenora Hope. The second strand is 1929, the year Lenora's family was murdered at the house, which she recounts by typing it out a page at a time. The chapters alternate between the two.

No. Hope's End, the Hope family and the 1929 murders are all invented. The setup does deliberately echo the Lizzie Borden case — the publisher's own jacket copy describes it as a "Lizzie Borden-like massacre", with a young woman suspected of killing her family and never proven guilty — but the novel is fiction and is not a retelling of that case.