A pre-teen novel of fantasy: When 10-year-old Ruthie tells her 12-year-old brother, Dan, that she has chosen "Noah's Ark" as the topic for her summer project, he doubts the wisdom of her choice. Cousin Jack, a student of ecology, agrees that the project is very ambitious. "Do you realize," he says, "that the Ark had to be a closed ecological system, which you will have to describe, apart from telling how it could have been built?" With cooperation and the help of her dreams, Ruthie completes her assignment.