Sylwanin and Neytiri say nothing, staring at Trudy as if the explanation is senseless. They exchange looks.

"Sa'nok!"

Grace lowers herself to the level of some of the smaller Na'vi children, greeting each personally and warmly. They greet her with questions about the day's curriculum and last week's lessons -- as well as questions about the strange Skyperson, of course. Some have never seen one up close before.

"Why do you fly?" Neytiri eventually asks Trudy.

Sylwanin remains silent, pacing a proud circle around the marine.