"Afternoon of the Elves" by Janet Taylor Lisle

Anything might happen in Sara-Kate’s backyard. For that matter, anything was happening.

For nine-year-old Hillary Lenox, being friends with Sara-Kate Connolly is a complicated business. Sara-Kate’s clothes don’t match, her hair’s a mess, and she’s known to spit at people when they make her mad. But when Sara-Kate shows Hillary the tiny elf village in her overgrown backyard, Hillary decides she can’t be as awful as all that.

Hillary is amazed by the delicate houses, the miniature well, even an intricate Ferris wheel made of bicycle wheels and popsicle sticks. But the more time she spends in Sara-Kate’s yard, the more questions she has. How come they never go inside Sara-Kate’s house? Why is Sara-Kate sometimes missing from school? And why hasn’t Hillary ever seen Sara-Kate’s mom? If Hillary can just look deep enough, she hopes, she will uncover the secrets of the elves—and of her new friend.