There is so much going on at the end, twist after twist, but it couldn't quite make up for the slow start. The story unfolds in alternating POV from the two sisters: Heather's chapters are set in present day, Rosie's take place in the past, starting when they were young teens.
With their mom in hospice, Rosie comes home to be with her sister after a five year absence. They haven't been close since Samuel disappeared, and Heather goes back and forth between thinking Rosie killed him (and may be after her) and wanting to mend fences. I really struggled with why Heather didn't come out and ask Rosie to tell her the truth straight out. All of Heather's hand-wringing angst made the book drag.
When the end finally comes and the truth is out...wow. I did not see all that coming. Over the top and pretty twisted, but it made me a lot more invested than I had been.