Tartan Magic Series by Jane Yolen

Welcome to Scotland, where magic runs through the land like the stripes in the colorful Scottish tartans. Everyone and everything here, it seems, has some wizardry--old folks at rest homes, dusty old card games, even cowardly dogs. The only ones without magic are American twins Jennifer and Peter, and they're the ones who need it most.

For use in schools and libraries only. While visiting relatives in Scotland, three children come to the aid of a refugee from the distant past, a young Pict girl escaping a massacre of her people.

On a midnight visit to a Scottish cemetery, Peter and Jennifer get caught up in a drama three hundred years dead--a tale of two star-crossed lovers and the man who betrayed them. Their bitter ghosts still haunt the graveyard, too angry to leave the world of the living . . . but all too willing to drag Peter and Jennifer into the world of the dead.