River At Green Knowe

Ida is English, Oskar is Polish, Ping is Chinese, and they're all spending the summer with Ida's Great-aunt Maud at the ancient, river-encircled house of Green Knowe.
As Great-aunt Maud only thinks about the book she's writing, and her companion Miss Bus only thinks about cooking, the children are free to do just what they like - as long as they come in for meals. And what a wonderful, magical summer they have.