Ever since Charlie Donlea's 'Twenty Years Later' got popular on BookTok, I've seen so many people get confused because they're actually talking about two completely different books. There's Donlea's thriller and then there's Kate Morton's historical mystery 'The Clockmaker's Daughter', which was originally published under the title 'Twenty Years Later' in some regions. It's a whole thing.
If you mean the Kate Morton book, the core story revolves around Elodie Winslow, a young archivist in present-day London who discovers a photograph and a sketchbook that connect to a famous Victorian artist and a mysterious woman named Birdie Bell. The narrative flips between Elodie's investigation and the 1860s, following Edward Radcliffe, his model and muse Lily Millington, and his sisters. Birdie is the linchpin, the 'clockmaker's daughter' of the eventual title, whose true identity and fate bind everything together. Morton's strength is how she layers these lives across time.
For Charlie Donlea's standalone, you're following Avery Mason, a TV journalist investigating a cold case from 9/11, and FBI agent Walt Jenkins, who has a personal connection to the original tragedy. The victim, Victoria Ford, left a letter to be opened twenty years later, which kicks off Avery's reinvestigation. The characters from the past—Victoria, her sister Samantha, and the people in their orbit—are just as crucial as the present-day duo piecing it all together.