The Swallows, Amazons and Ds are camping in the Blackett family's garden at Beckfoot. The "Swallow" is not available for sailing. James Turner (Captain Flint) has sent word that he is returning from an expedition to South America prospecting for gold, and has sent "Timothy" ahead. As he can be let loose in the study, the Amazons and D's have already deduced that Timothy is an armadillo, and Titty, Dick and Peggy make a box for him, but he does not arrive. Slater Bob, an old slate miner, tells them a story about a lost gold vein in the fells. As Captain Flint has been unsuccessful in his prospecting trip, the children plan to prospect for gold on "High Topps" instead, as a surprise for Flint.