Thea's friends the Thea Sisters head to Australia to solve a mystery. A flock of sheep at Nicky's family's ranch is losing all its wool, and the ranch depends on the wool to stay afloat! Maybe the sheep's cure lies in an Aboriginal medicine containing a strange root. The five girls set off on a tour of the whole country to find out. It's a truly memorable outback adventure. Readers will love following the clues to help Thea's friends solve the mystery.