End of Days
At the end of the novel, Libby solves the crime, Ben is exonerated, and Patty… well, Patty is still dead. This isn't a time-travel novel. But at least we learn exactly how she died, and that she did it with her family's best interests at heart.
A recurring motif for Libby Day is that she goes into the past to fix the future. She has to confront the massacre that eliminated most of her family in order to find out the truth. So it's fitting that the ending reenacts the beginning in a way. When Libby discovers that Diondra is the killer, she has to hide from Diondra in the woods, much like she hid from the killers in a field when she was seven years old. Thankfully, Libby doesn't lose any extremities to frostbite this time. Poor woman has enough scars.
Instead, Libby's able to heal some scars this time, by realizing that her brother Ben didn't actually kill her whole family. Of course, she does seem to forgive him pretty easily for not stopping Diondra from killing their sister, Michelle, as she "matched palms" (40.37) with Ben on the glass at the jail. But maybe no one liked Michelle, after all.
Libby also makes up with another surviving member of her family, Aunt Diane. Then she drives past the old family home, seeing it for the first time since everyone was killed there. A new family has moved in. "Our farm was a farm again" (42.13), Libby observes. Life goes on… after a deep clean.
Now, Libby actually wants to go home, "away from Darkplace" (42.14), and figure out how to live her life. She's done with dwelling on the past.