How much more could be learned about using and conserving ocean resources if humans could communicate with intelligent marine creatures? This question is sure to intrigue readers who follow the adventures of Mo and Duke, a lonely girl and a dolphin who develop a deep friendship when they learn how to use whistles and mental linkages for communication. Duke, a curious young dolphin, was poisoned by contact with poisonous blue slime in the hold of a sunken ship. Paralyzed and unable to swim, the dolphin’s pod brings him to the Duke University Marine Lab dock where a dolphin rescue team saves his life. Mo, a lonely young girl who lost her ability to talk in a freak plane accident, has no friends other than Fetch, a big black retriever. She is strongly attracted to the sick blue dolphin whose hammock in a dock-side enclosure enables him to breathe. She becomes an important part of the dolphin rescue team, keeping his skin moist and feeding him daily. Mo’s heart is touched when she senses that the dolphin, cut off from his pod, shares her sad and lonely feelings. To ease his loneliness, Mo whistles to Duke as she cares for him. Duke slowly regains his health and notices the young girl and her whistles. One day Duke whistles back, beginning their remarkable whistle-talk communication and growing friendship. As Duke regains his health, Mo and Duke further develop their whistle talk and occasionally share mental linkages. Mo shows Duke computer images that tell him about her life on land. Duke sends her mental images of his life in the sea. Never have humans and dolphins shared this way. Mo and Duke keep their ability to communicate a secret. She would not forgive herself if Duke were kept captive for study in a research facility because she revealed their communication ability. Mo bravely faces the loss of Duke’s company when he is well enough to be set free. When Duke locates his home pod, Mo gets a final ride with her friend and lets him go. Duke becomes a free dolphin once again.