On the planet pk-l7, humanity thought it had found the answer to its prayers when xenium was discovered there. This substance could be used to make a powerful fuel that would send civilization across the stars. But, as mining operations got underway, the seemingly peaceful aliens changed, becoming murderous. Now, few survivors are left, including green Squad, a Group of operatives that had been deep below the surface when the attacks started. Who will make it out of the tunnels alive? Dark side is a standalone expansion for zombicide: invader. Players take on the role of members of green Squad and must fight their way through a 10-mission campaign, battling the dangerous and deadly Driller xenos along the way. Will it be humanity or the aliens that make it to the surface first?