While the other caged animals in the laboratory plead for freedom in their own languages, Leaper, a Kangaroo rat, manages to speak to the scientists in English, telling them she has "come to talk ... about a matter of life and death." Overwhelmed by this breakthrough in human-animal communication, the researchers ignore her pleas for aid against a "monster" who threatens her desert home. Julian, a twelve-year-old helping out at the lab after school, attempts to help Leaper, only to find that he is unwittingly linked to the destructive menace. The ethics of animal research and habitat protection are explored in this fast-paced adventure illustrated with black-and-white sketches. (Ages 8-10)