Summoned by their eccentric friend Professor Challenger, Edward Malone, Professor Summerlee, and Lord John Ruxton travel to Challenger's country estate, bringing with them—at the behest of their host—several canisters of oxygen. As the journey progresses, Malone recounts tales of strange goings on around the world and the behavior of all three men grows increasingly erratic. Reaching a pinnacle of bafflement, they arrive at the house of the outlandish Professor and are regaled with an eccentric theory involving their experiences and an apparent impending apocalypse. A dramatic departure from Conan Doyle's well-loved detective fiction, this is an engaging work of science fiction that provides a valuable glimpse of the author's incredible creative range.