The signal arrives from deepest space. Landon Walker-Earth's radical expert in communication-refuses to believe that it's a warning. Called back to headquarters in Brazil, he reluctantly teams up with other top scientists to decode the message. At the same time, shamans in primitive societies around the world seem to know what the signal means. But they're all dying for their effort. Decoding the signal may lead Landon to the same fate. And then the signal targets Landon's baby daughter, and suddenly its message becomes crystal clear. He must act to save her-and all of Earth.