I LOVED the first 3/4 of the book. 
The twist was kinda meh and didn't live up to the potential it had.

Honestly I found this book randomly on Libby and after reading the description I thought it was the book that inspired the movie, A Simple Favor. I had watched that when it first came out a few years ago and besides the fact that there were no children mentioned this seemed similar and made a big deal of mentioning those words. 

After starting, it was pretty obvious that it has nothing to do with that but it was really good anyway and had me hooked from the first few minutes. It was a little predictable but still intriguing because the author does a great job creating atmosphere. The choices made by the main character get progressively more stupid as the book goes on. But up until

she steals a gun and willingly follows a stranger to an unknown (clearly dangerous and high up) second location with absolutely zero reason other than blind curiosity AND doesn't tell anyone where she's going,

its easy to support her silly decisions. That whole scene at the climax was pretty disappointing to me but not enough to ruin my enjoyment of the book up until then.
The last bit leading up to the end was not believable and felt off character, but I did like the very end. 
I'd definitely recommend as a fun little mystery but dont go into it with too much expectation :)