Here we have three different time periods. The earliest – the highschool years – we hear about mostly through the recollections of the characters.
The middle time period is set in the 90s. Lots of references there, and if you’re genX, you’ll often find yourself saying “heh” out loud a lot. (Hey, remember blockbuster? And needing to save documents every five minutes while writing? And Stone Temple Pilots?)
The last time period is some time close to current day.
You also have the perspective of four different friends, plus a small town detective, as well as some poor fisherman who finds the monster lady, and if that’s not enough – we also see these events through the eyes of several random side characters.
And every one of these characters want to tell you about the things they witnessed. So while the prose is very well done (snails in mouths! Super creepy!) the plot dragged unnecessarily. And unfortunately there wasn’t much pay off at the end as there wasn’t much of a mystery. By the time the first of the people in the friend group dies in the middle time period you know how it’s going to conclude.