Many years ago, the DC Comics universe consisted of a multitude of universes, all separated by vibrational frequency, that housed multiple versions of beloved characters.  Then, in an attempt to streamline things, DC Comics experienced its Crisis on Infinite Earths, which left one universe standing with one timeline.  Over the last few years, something like that has happened with the DC Comics shows on the CW.  Shows like Arrow and The Flash happen in the same universe, but they have to travel across dimensions on order to engage with Supergirl or Batwoman.  That changes this Sunday, it seems, when the CW stages its own Crisis on Infinite Earths.  They’ve been building to it for some time.  Here’s the final trailer.

There’s a lot going on in the trailer . . . and a lot that the showrunners have NOT revealed to those trying to piece things together, particularly in what kind of other characters might appear (and what universes they hail from).  That, I think, will be part of both the joy and the heartbreak of the story.  Worlds will live . . . worlds will die.