After a series of expeditions—some successful, some not—to the icy Siberian tundra, corruption has spread from animals and humans to a much greater threat. New heroes, better prepared than their predecessors, gather to face the prospect of a mechanical monster, but the changing landscape brings more uncertainty as they explore Tunguska with fresh eyes.

The Gears of Corruption expansion for Expeditions adds elements of risk and danger in the form of secret bonuses on map tiles and a corrupt mech that roams the land. To counter these threats, the expansion offers 2 new mechs and 4 new character/companion pairs, as well as components for a 6th player. Gears of Corruption also speeds up early game progression by giving players starting resources and a hero worker that can act as any worker type.

The Gears of Corruption Ironclad expansion includes 2 metal mechs, 6 rubber base snaps to update the original ones and has a foil box.