Someone has stolen Thud's computerized maps and intends developing the island as a luxury marina resort. But how is he going to do a site visit when he can't even see the place? Meanwhile,Thud is hosting an international balloon race and all the world is visiting. Who will win this time? A balloon? Three juvenile kidnappers? A sixteen-year-old hacker - or a small white cat? Several characters old and new come together for the last tale in the series.