The Sub Terra core box is required to play this expansion.

You have returned to the caves and you are not alone!

A new threat has emerged from the darkness, faster, more dangerous and ready to hunt you down... Employ a powerful Mercenary to defend against this invasion and bring to the surface evidence of its emergence. You have no right to fail!

Extraction adds more horror to the cave with the new fast-moving jumper hazard map. Fight them with the Mercenary, a flexible mix of cautious explorer and powerful defender. First and foremost, you must bring proof of the infestation to the surface, or die trying...