The Exodus of Clan Ironbeard

Many milennia ago, when the Aliens took over the world, a tribe of dwarves known as the Ironbeard Clan found refuge beneath the Gray Spine mountain range. The dwarves dug a vast network of underground passages, and lived in seclusion.

A colony of Aliens on the surface preyed upon the dwarves, conducting raids in which they abducted groups of dwarves, selling them on as slaves to other Alien colonies.

The dwarves took action, building a Working, a great Portal to keep the Aliens out. The portal drew power from natural resources. Skilled dwarven engineers carefully crafted the portal to grant access only to their kin, so that any dwarven diaspora who managed to make their way back to their ancestral home could get inside.

Thwarted, the Aliens retaliated. They could not get in, but they could keep the dwarven diaspora out. The Aliens installed within the portal a race of incorporeal beings, known as Elementals, to prevent any returning dwarves from opening the portal.

A band of dwarven refugees hire the party to deliver them safely to their homeland.

The Exodus of Clan Ironbeard is an old school adventure for character levels 5-7.