Federated Colonies Deputy Marshal Sarah Reeth has lived with guilt since she was nine years old. Her best friend, Tillie, was abducted at a fair though Sarah stood only about twenty feet away. Sarah caught a telepathic whiff of the kidnapper but not in time to stop him. The emotional damage to Tillie was irreparable, and the questions "why her and not me" and "could I have done more" have haunted Sarah ever since.

Now, at another crowded, busy fair, Sarah picks up the same telepathic impression during a kidnapping attempt. The intended victim escapes, but Sarah and her fellow marshals vow to catch the predator, who's also a telepath. It's psi versus psi in Sarah's quest to finally deliver justice for Tillie.