The Wizard's Map by Jane Yolen

The Wizard's Map by Jane Yolen is about twins, Jennifer and Peter, their younger sister Molly, and their parents. They all travel to Scotland to spend time with the people who helped raise mom. Once they arrive, they start to learn that the small town where they'll be staying this summer is not quite normal. Jennifer and Peter find a strange map in the attic of Gran and Da's house. Molly drew some circles on it that night, and the next morning, crop circles appeared in the wheat fields of their neighbor! Also in the attic is a card game called Patience. Jennifer knows this game is somehow connected to the map and the strange garden house in the back garden. She wants to go exploring, but is frightened of the crazy things that keep happening. Then, a stranger shows up at the house and literally DISAPPEARS with Molly! It's up to Jennifer and Peter and a strange threesome of a black dog, black dragon, and black unicorn to save Molly and the rest of the family from the evil wizard who created the map hundreds of years ago.

This was a great book! It's the first in the Tartan Magic Adventures. The story unfolded quickly and kept my attention all the way through. Jane Yolen does a nice job of writing so that I could visualize all of the events and characters in the story.