Necromunda is set in a vast underground metropolis known as the Underhive, where gangs and other factions vie for power in a harsh environment. Supplements like "Halls of the Ancients" usually expand on the game's lore, provide new rules, factions, terrain, or adventures for players.

The expansion includes a 6-week structured campaign, The Helios Legacy. Each player controls a “Prospector Token” that moves across a branching map of the Helios-Ex Machina complex.

Campaign stages:

Post-campaign — Gangs can sell their archeotech for a massive credit boost, or keep it for narrative play, but permanent corruption scars remain.

Without a direct link or more context, it's challenging to provide specific details on the "Halls of the Ancients" PDF. However, based on the title, it could be a scenario, campaign, or sourcebook for Necromunda that involves ancient ruins or technologies. Such settings are common in Necromunda, often providing backdrops for adventures, treasure hunts, or combat scenarios.

In the 41st millennium, the under-sifts and ash wastes of Necromunda hide secrets older than the Imperium itself. Halls of the Ancients focuses on the discovery of the Helios-Ex Machina, a sprawling subterranean research complex from M21. Inside: functioning automated factories, gene-locked vaults, and the coveted Halls of Ancients — data-crypts containing pre-Imperial knowledge.

Gang leaders (and their patrons in the noble houses) race to claim:

Necromunda: Halls of the Ancients is an official expansion book for Games Workshop’s cult skirmish game, Necromunda. Released as part of the Necromunda: Ash Wastes narrative arc, this supplement plunges gangs into the perilous, forgotten ruins beneath the planet’s surface — and across the ash wastes. The “ancients” refer to the technologically superior human civilization before the Imperium, often linked to the Dark Age of Technology.

Unlike standard zone mortalis or sector mechanicus battles, Halls of the Ancients introduces: