Why not? That'd be a hell of a premise and twist on the Arcanum setting. Time period is perfect for it too. Heat weapons for technies All sorts of alien mutagen chemicals that turn lifeforms into other lifeforms Upgrade your charged automatons into Tripods, and maybe drive one! How could the aliens be repulsed? Same old disease as in the original story? Can Arcanum's scientists reverse-engineer enough of the alien technology to fight back on even terms? Some old magickal artifact? Refugees taking shelter in Dwarven mines, the Glimmering Forest smothered by crawling red creep, armies be they are arcane or wielding state of the art canon and gun reduced to ashes. Perhaps a desperate mission to find safe refuge or some ancient artifact 20 Thousand Leagues Under the Sea?