From the introduction:
decade ago in the Mwangi Expanse, a Pathfinder expedition went horribly wrong. Initially things proceeded well as the team travelled deep into the jungle to explore the Doorway to the Red Star. This odd locale was once the stronghold of the King of Biting Ants, a legendary scourge of the Mwangi people in the Age of Anguish who was ultimately defeated by the even more legendary hero Old-Mage Jatembe. In spite of the passage of thousands of years, the Doorway’s ruins remain largely unexplored, due to both its remote location and its somewhat taboo reputation among locals. The Pathfinder expedition was among the first serious surveys of the site undertaken in recent history, having successfully documented the more easily accessible ruins and found significant artifacts of the past. As they progressed, they began to encounter otherworldly creatures and hazards that exceeded their abilities, and they wisely cut the mission short to return home with their findings and treasures. A secondary goal of the expedition was to map the nearby region and update the Society’s knowledge of the Expanse. In doing so, the team unwittingly crossed into Mzali territory. Unfortunately, they never made it back.