The Boundary Beyond is the second Mythos Pack in The Forgotten Age cycle
As the thread pulls, the weave unravels. Following the events of Threads of Fate, you are driven from Arkham to Mexico City to find answers about an enigmatic relic and those who pursue it. After a seemingly endless string of failures, it appears the trail has gone cold. But on the very day you are ready to return home, something is wrong—the city has altered. Silver lightning crackles in the sky overhead, and the earth rumbles below your feet. Monstrous entities float just below the clouds and the architecture looks more like something out of a history book than modern Mexico.
The Boundary Beyond scenario skews your idea of reality as the city shifts around you. By using the Explore action to investigate different locations, you may find that time has become destabilized as Modern locations are replaced with Ancient ones. You must discover a way to restore the proper timeline before the city and your fate become completely unalterable. Will you be able to return, or will you become lost in time?