From the Synopsis: During a Numenera game, player characters are entirely likely to accidentally—or purposefully—travel to another plane of reality. Things are different in alternate dimensions, sometimes so wildly that players have a hard time figuring out where to begin sorting out the environment. Other times things are just slightly different, as in the case of the thousands of parallel planes where things in the Ninth World are somewhat like the published setting, except for a few historical deviations that created a spectrum of diverging possibilities. Whatever the case, the GM will find it useful to have a few extra tools in their toolkit for dealing with situations beyond even the already weird Numenera status quo.