"The end times approach.
To everything there is a season, every campaign has to come to an end sometime. So why not go out with a bang?
The Apocalypse Stone is an epic adventure to challenge high level characters.
But beware, it will destroy your world."
This adventure is a literal universe-ender. Past a certain point in the campaign, there is nothing the players can do. The world *will* end.
This needs more information from someone who actually owns the module. Given descriptive text is just "what's on the back". Outside of that all information is second hand.