Quote Originally Posted by PairO'Dice Lost View Post
You can't time travel between 3e and 4e, as 4e is obviously an alternate Mirror Universe timeline where all the PCs' equivalents wear goatees, and said timeline is rightfully stricken from existence by the end of the adventure.
On a related note, one of my headcanons is that the Abyss contains chaotic evil alternate versions of all the other planes