World War II has just ended a few years ago after the events of the Fall of Berlin. Events happened with the following in '46; "Berlin is encased in an impenetrable black barrier. The war drags on as Allied forces battle mutant-plagued battlefields, V2 rockets bearing occult payloads, and rogue warlords wielding alien technology."
In 1952 our party of adventurers lost their cyclotram vehicle and barely made it out of Pellucidar. So the party of adventurers were trying to recover a cyclotram from the Fourth Thul organization at one of their inner Earth bases. The party were able to locate a secret tram elevator deep into the inner Earth. There they find an abandoned tunnel and it leads deep into a well shone up mining style tunnel.
The Fourth Thul organization's members were actually working from the "Engstrand Geological Expedition's journals, diaries, and publications. These were stolen from Arkham university and the Fourth Thul found the expedition's base camp which had been expanded into a base. These events are connected too
OSR Campaign Slab - Amazing Adventures Rpg - Weird War II Campaign
Our adventurer's sorcerer cast a sleep spell on the guards around the hanger holding the Cyclotram and silence spells on the hanger. Guards were killed and our party went straight toward the cyclotram hangers!
The party also found a hanger where the Fourth Thul were doing restoration work on an old Victorian mole machine for inner Earth exploration left behind by the failed the "Engstrand Geological Expedition" of 1938. The Expedition only had two survivors who climbed out of a fissure in a New England extinct volcano. Our adventurers planted fusion charges around the Victorian mole machine and the player's PC's went to steal the cyclotram to get back to Pellucidar.
The PC's started the atomic batteries of the mole machine and the cyclotram was launched onward toward Pellucidar! Then game time four hours later the random encounters happened! Geothermal Vent Burst: Toxic sulfurous gas fills the area. (Requires a Physical / Constitution Prime check to avoid fatigue/damage). Fortunately the Cyclotram has atmospheric protections!
An inner Earth (or Hollow Earth / Subterranean) adventure in Amazing Adventures RPG thrives on pulp action, ancient mysteries, bizarre science, and lost civilizations.
Below is a d100 Random Encounter Table tailored for the SIEGE Engine mechanics of Amazing Adventures. It is divided into narrative categories so you can quickly improvise combat, exploration, hazards, or social encounters.
Inner Earth Random Encounter Table (d100)
| Roll (d100) | Category | Encounter Description |
| 01–10 | Prehistoric Fauna | A herd of Pteranodons roosting in giant bioluminescent mushrooms; or a hungry T-Rex tracking the party's scent through dense jungle ferns. |
| 11–20 | Lost Civilizations | A scouting patrol of Subterranean Lizardfolk (or Serpent People) wielding obsidian spears and strange, ancient crystal technology. |
| 21–30 | Subterranean Hazards | Geothermal Vent Burst: Toxic sulfurous gas fills the area. (Requires a Physical / Constitution Prime check to avoid fatigue/damage). |
| 31–40 | Weird Pulp Science | A crashed 1920s Steam-Powered Mole Machine or Nazi/Ahnenerbe drilling rig, half-buried in glowing mineral deposits. |
| 41–50 | Bioluminescent Wonders | A forest of Glowing Crystal Pillars that hum with psychic energy, causing strange hallucinations or altering magnetic compasses. |
| 51–60 | Unlikely Explorers | An NPC expedition in distress—a rival group of Victorian or 1930s archaeologists trapped by giant subterranean arachnids. |
| 61–70 | Abyssal Predators | Blind Cave Horrors: A pack of albino, echolocating apex predators stalking the party from the cavern ceiling. |
| 71–80 | Underground Waters | A vast Subterranean Ocean: A giant prehistoric sea monster (Plesiosaur or Mosasaur) capsizing a primitive raft. |
| 81–90 | Ruins & Relics | A towering Atlantean / Lemurian Temple guarded by automated stone or brass guardians activated by movement. |
| 91–00 | Cosmic / Eldritch | A rift leading to a Void Cavern, where gravity breaks down and otherworldly entities whisper secrets from the dark. |
Deep-Dive Encounter Highlights
Here are four expanded encounters from the table ready to run at your table:
1. The Steam-Mole (Roll: 35)
The Situation: The party hears screeching metal and smells burning diesel. They discover a giant iron drill-ship wedged into a basalt wall.
The Twist: The crew is dead or mutated by glowing crystals inside the drill core. However, intact logbooks reveal a map deeper into the Earth, and usable ammo or tools can be salvaged.
2. Serpent-King's Outpost (Roll: 18)
The Situation: A patrol of 4–6 Serpent-kin warriors block the pass, demanding tribute or sacrifice for their "Inner Sun" god.
Mechanics: A successful Mental / Charisma or Language check allows negotiation or trickery; failure leads to an ambush using blowdarts with hallucinogenic venom.
3. The Gravity Fault (Roll: 95)
The Situation: The cavern ceiling and floor invert. Floating islands of rock drift across a subterranean sky lit by a miniature central core.
Challenge: Crossing requires dexterity, ropework, or acrobatics while dodging flying, bat-like reptilian scavengers.






