In each season of Friends at the Table, the players tell stories using different roleplaying games. Twilight Mirage is Season 4, and it picks up tens of thousands of years after the story of Counter/Weight in Season 2.
While there aren't many direct callbacks to Season 2, if you're jumping in for the first time, there are a few broad concepts that you'll want to know:
Divines are machine-gods, created by humans for protection and guidance. In Season 2, these tended to be giant humanoid mechs, with names that reflected democratic virtues like "Liberty" and "Righteousness." Each divine had a human pilot, called a Candidate.
The humanoid design of Divines leads to one of the core themes of Season 2: "We could have built them to look like anything, but we made them look like us."
In the intervening centuries the role of Divines has expanded: New Divines were created by humans, other synthetic life forms, and even other Divines. They now take a much wider variety of forms, from giant library ships to swarms of drones. Divine pilots are now known as Excerpts.
The Mesh Edit
Now known as The Veil, the Mesh is an augmented reality space. Virtually everyone can see the Veil, whereas in Counter/Weight this was visible only to certain select individuals from the planet September known as Stratii. The Veil allows people to heavily customize their appearance and the appearance of the environment around them.