Discovery
At the xenoarchaeological dig outside of Foothold City evidence of an advanced technological race is found.
The Swarm
While more mysteries of the alien city are slowly uncovered, events are interrupted by the sudden arrival of an invading force of Invid.
Nemesis
With the Invid defeated, attention turns back towards the alien city. Most disturbing is the discovery that the aliens fled millennia ago in the face of a cataclysm, a cataclysm that looks destined to repeat itself very soon.
Next: Into the Unknown