内容简介：
Pobby and Dingan live in Lightning Ridge, the opal capital of Australia. They are friends with Kellyanne Williamson--"indeed, only Kellyanne can see them. Pobby and Dingan are imaginary. Ashmol, Kellyanne's brother, thinks his sister should stop being so childish--"until the day when Pobby and Dingan disappear, the same day that his father is accused of rarring, the worst sin an opal minder can commit. Ashmol helps his grief-stricken sister, recruiting the whole town in search of the friends. In the end, he discovers that only he can find them, and only if he too believes they are real...