Full disclosure: It is hard to discuss this book without getting into spoilers. I will try my best, but keep in mind the book has several parts and each part has a twist.
I absolutely adored the concept. Answering deep questions and telling dark secrets to a complete stranger for research? Weird, creepy, and, yes please!
Unfortunately, after the first "twist" the plot quickly unravels into just complete weirdness. I was able to figure out the first one (the cover is a hint, by the way) and was disappointed. We are in the late two-thousand-teens... this should not have been a surprise.
The rest of it is where it gets more murky for spoiler territory, but it was pretty obvious what was going to happen at each turn. I almost feel this would have been better off as a movie because it would have been a bit harder to follow along. The book is a quick read and thrilling, but ultimately, I was disappointed.