Holmes, Sweet and Holmes, the intrepid explorers, set forth on their expedition to Sagrada, sailing via the Bay of Biscay: after trekking through tropical rain forests, paddling in a canoe up the 'langurous Salamander river', riding on camels across the vast desert, they eventually reach the goal of their journey. As they wearily make their way homewards one by one they drop down dead in the desert, leaving their bones to whiten amid the illimitable sands...