Plutonia is a 1915 (first published in 1924) Science Fiction novel by Vladimir Obruchev about the journey of an explorers' group to what turns out to be a void inside the Earth with an entire separate biosphere. The novel turned out to be so realistic that the readers offered Obruchev help with organising a new expedition; he had to write a foreword explaining that Plutonia is a work of fiction and that the theory of the existence of a void filled with air inside the Earth had long been discredited.
The novel contains examples of:
- Action Pet: General is a Heroic Dog who often aids the explorers in fights or helps them to find each other in the wilderness.
- Adaptation-Induced Plot Hole: Trukhanov first meets with the explorers to tell them the basics about the expedition, and a week later, everyone gets together again to confirm their participation — "except for the captain who has already gone to the ship". However, the captain wasn't at the previous meeting at all. The error stems from the post-World War II revision of the text, since in the early edition, the Norwegian captain does attend the first meeting.
- Amazon Brigade: The Palaeolithic women are no less capable at fighting than men and launch an attack on the explorers at one point.
- Ant Assault: A colony of aggressive Jurassic ants gives the explorers more trouble than the rest of Plutonian fauna put together, stealing most of their supplies and seriously injuring General. Eventually, after a lot of planning and a difficult search (all of it with barely any food and water left), the explorers find sulfur and poison the colony with sulfur dioxide. A while later, another colony attacks the group, and they barely manage to fight them off.
- Badass Bookworm: Except for Maksheev and Igolkin, the members of the expedition are all celebrated scientists, but they prove themselves quite adept at dealing with a Wilderness Survival Plot and fighting off prehistoric predators.
- Bilingual Backfire: When The North Star is stopped by the Austrians, Trukhanov asks to talk with their captain, saying that he only speaks French and English but not German. The Austrian officers agree and take Trukhanov to their ship; unbeknownst to them, he is fluent in German and is able to understand their plans concerning the fate of The North Star and its crew.
- Chekhov's Volcano: The explorers need sulfur to fight the ants, and sulfur can be found in a nearby volcano. Only a few pages later, the group has to deal with another problem in the form of a starting eruption.
- Chromosome Casting: The main characters are all male. The only named woman is Katu, a Plutonian from a Frazetta Man Palaeolithic culture.
- Defiant Captive: Katu is injured and taken prisoner after a fight with the Palaeolithic people. The explorers try to persuade her to accompany them to Russia, but she adamantly refuses and finally escapes at the first opportunity. They are very disappointed that they wouldn't have an actual Palaeolithic human with the group but agree that it would be both cruel and impractical to look for her again when she very clearly prefers to return home.
- Direct Line to the Author: The narrator claims to have read the diary of one of the explorers and based the book on it.
- Downer Ending: The explorers initially return home safe and sound, but all the materials from the expedition have vanished in the wartime turmoil. After ten years, all the members of the group have either died or gotten killed in World War One or the civil war in Russia. The Sole Survivor is Trukhanov, living as a hermit in his observatory; his own disability prevents him from traveling to Plutonia in person, and he has lost all hope of ever recovering the Plutonian collections. On top of it all, Plutonia's "sun" is in its last phase, so the ecosystem can collapse at any moment.
- Dream-Crushing Handicap: The expedition to Plutonia is Trukhanov's cherished pet project, but he can't go there himself because he has a prosthetic leg.
- Grim Up North: A journey across the polar regions is no picnic, and Trukhanov warns the explorers they risk their lives by going on this expedition. Indeed, before the group reaches Plutonia, they barely make it through the snow and ice.
- Friendly Enemy: The Austrian officers who stop the North Star are quite polite and even compassionate (one of them is the son of a polar explorer himself). However, they still confiscate the ship and all the collections from Plutonia.
- Hollow World: Plutonia is located in a large void inside the Earth.
- Idiot Ball: Papochkin decides to go back to a volcano that's starting to erupt because he has forgotten his gun in the crater (for extra idiocy, it's not even the only gun the group has). He barely escapes with his life.
- Mistaken Nationality: In the early editions of the novel, Maksheev is briefly believed to be Scottish when he starts speaking fluent English and introduces himself as Jacob Macsheef. The later editions, due to the changes in political climate, removed both the North Star's captain's Norwegian origins and the references to Maksheev's work in America, so Maksheev speaks Russian from the start.
- A Molten Date with Death: Discussed and narrowly avoided. As the Plutonian volcano erupts, Kashtanov recalls the 1902 eruption of Mount Pelée
and says that, like the residents of Saint-Pierre, they could have been burned by the volcanic gases (or crushed by pyroclastic rocks). Only thanks to the wind blowing the pyroclastic surge in a different direction are the explorers able to escape. - Not So Extinct: Plutonia is home to a wide range of prehistoric biota, up to and including the Jurassic.
- Precocious Crush: Katu has a bit of one on Borovoy, which leads to her throwing a dart at the explorers in an attempt to make him stay at Plutonia.
- Put on a Bus: Borovoy and Igolkin stay behind on the edge of Plutonia to watch over the supplies and most of the equipment and are absent for the entire voyage arc. However, they get their own subplot closer to the end when they are imprisoned by Palaeolithic people.
- Scenery Porn: The landscapes (even the non-fantastical ones) are described very carefully. Even the mundane view of a small, sleepy harbor gets a long paragraph devoted to it, and the description makes it look breathtaking.
- Shown Their Work: The author, being a geologist and geographer, describes the journey to Plutonia in meticulous detail.
- Sixth Ranger: Maksheev joins the expedition when the North Star is already on its way to the Arctic. Unlike the rest of the team, he is a Thrill Seeker adventurer (with a mild case of gold fever) and an engineer rather than a scientist.
