An extremely wealthy but reclusive man has died, leaving an eccentric will which hints at great riches hidden somewhere in the house. Most of the people at the reading of the will did not know the deceased in person, but had received kindnesses from him, for instance by the payment of school and university fees. The principal beneficiary, a great-nephew, also did not know him. The only two people who really knew him were the old lawyer who dealt with his affairs, and an old Indian servant. Yet when the will had been read, and they all went to where the treasure–gold, jewels and bank-notes–were supposed to be hidden, nothing could be found.
Joe Carstairs is a boy on a farm in Australia. His father is a keen naturalist who, some years before had set off for New Guinea in search of specimens, and never been heard of again. Joe is old enough to mount a search expedition, and takes with him a local doctor and an aboriginal worker on his farm. They find themselves joined by a stowaway, Jimmy, whose father is a squatter (farmer) nearby, together with his dog, Gyp.
This team sets off, arrive in New Guinea, hire some more porters, and travel guided by some sixth sense straight to where Mr. Carstairs has been kept a prisoner, along with another Englishman, whose mind has gone, under the stress of his imprisonment.
There ...