Reunited for the summer the Swallows & Amazons with Dick & Dorothea launch a prospecting expedition to find the lost gold mine of the high hills above the lake But the mining camp runs into all sorts of trouble not only the danger of fire in the drought ridden countryside but also scary encounters with unsafe tunnels Worst of all is the sinister Squashy Hat who appears to be a rival prospector & who's certainly a spy
- how can they keep working without him discovering what they've found?