By R. L. Stine
In the book that started Goosebumps, a family inherits a big old house in a town called Dark Falls, where the friendly neighbors turn out to be dead and the town needs living blood to keep itself going.
Amanda and Josh's family inherits a house in a town called Dark Falls, and something is off from the very first night. The house groans, the new neighbors are pale and cold, and the children they meet keep disappearing whenever the sun is out. Little by little Amanda pieces together the truth: everyone in Dark Falls is already dead, the town needs a living family to feed on to keep going, and that's the real reason her family was invited. She and Josh have to find a way to fight back before they end up permanent residents too. Chapters are short and almost all of them end on a cliffhanger, so it moves fast.
For a lot of children this is the first real scare, the step up from spooky-cute for one who's begging to be properly frightened and has decided picture books are for babies. The frights are the fun, roller-coaster kind rather than anything gory, and the short cliffhanger chapters keep even a reluctant reader flipping. It's also the book that kicked off the whole Goosebumps line, so if it clicks you've handed them dozens more at about this same fright level, and a year of bedtimes sorts itself out.