I was a huge fan of William Sleator's books in junior high. Our school library had Interstellar Pig and House of Stairs, both of which I must have read three or four times. And I saw this book at that bookstore, and thought, sure, why not?
Run revolves around Lillian, Mark, and Jesse. Lillian is staying alone for a couple of days at her family's summer house, which has proven to be more daunting than she thought it would be originally. Mark and Jesse are supposed to be on a bike trip to visit some friends. Lillian finds herself worried about being alone, and the boys find themselves blocked from continuing their trip by the weather. And objects keep disappearing from the house when they're out. And Lillian and Mark are both sure they saw someone in the woods nearby.
It's a book written for a younger audience, but I appreciate the effort Sleator makes to not go trite or easy with things. There ends up being a whole thing about drug addiction in there, but Sleator makes certain to point out it isn't strictly a function of economic status, and that the structures in place meant to help are woefully insufficient. The three teens had earlier met a cop who had basically treated them like idiots who were immediately suspicious because they were young, and so they opt not to call the police. Sleator doesn't have this turn out to be a great decision that works out well for everyone, because fuck the police or something like that. Their reasons aren't exactly wrong, just not thought through well enough.
The basic idea seemed to be that wanting to help someone isn't wrong, just keep in mind that to really help them is not going to be some simple, easy process where you do one thing and magically fix everything. It's still worth doing, just be prepared to make a genuine effort.
So the book wasn't precisely what I was expecting. I had figured on something with probably a supernatural bent, maybe science fiction, and it's more grounded than that. Not bad, just different.