1) The Citadel of Ricks is no more
The first episode of season six, “Solaricks,” picked up immediately after season five’s finale—a somewhat unusual move for Rick and Morty, but there was major plot fallout to address after the Citadel was destroyed by Evil Morty. So far we haven’t seen Evil Morty pop up in season six, but that’s not surprising for a series that prefers to sprinkle its episodic moments in between random adventures.
