Reunited for the summer, the Swallows and Amazons with Dick and
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 and who's certainly a spy - how can they keep working
without him discovering what they've found?