Fantasy for children - Siblings mover away from thier cousins of the same age, and greatly miss them. Before moving, the children would play a fanatsy make-believe game, pretending to be royalty, acting it out, and so on. After moving, they discover a way to connect for real in the make-believe world. And it's in the middle of a crisis! They have to play their assigned parts, and still get home in time for supper. I did not find it very interesting, and neither did my children, who are used to fantasy. It might be more interesting for a newbie in the fantasy world.
Not up to Tam Lin, in my opinion... but still Pamela Dean. I remember this book took me a long while to track down.
