"In Avalidad there are urban legends about Agartha, an underground town inhabited by mutants and other outcasts.
'As Above So Below ' works because it places the PC's within the line of sight of several factions at once. The crooks, the law, and forces from beyond. And it does this while moving through its internal timeline. And 'As Above So Below' is a solid addition to the 'Post Cards From Avalidad' rpg!