Nightfall is an odd one, because I definitely liked the idea and the atmosphere well more than the actual book, so much so that I pushed through to the end. I am absolutely not the kind of reader who must finish everything she starts -- I abandon things all the time -- so that I kept trucking is decidedly in this book's favor. That said, I still wasn't super jazzed about Nightfall, so.
Three teenagers -- a sibling pair and another boy -- live on an island on a planet where the seasons are incredibly long. (Think Game of Thrones without the incest.) The entire community of the island comes in the spring, and leaves 14 years later in the fall. At that point, the island is given over to ... something, and everyone must leave their habitations just so. The teens get left behind in the push off the island, and must either make it through Night, or get off the island somehow in the cold and dark.
The environmental stuff was bananas good, and I was all in on the descriptions of the changing seasons and the changing island. The teens, maybe not so much. Several footballs are hidden for so long that it was almost insulting, plus it just made it hard to care. I also didn't find the ending particularly satisfying, but, per usual, ymmv. Winter is coming, I guess.