This entire episode was needed for the storyline of season 3, every 10 or so episodes I'll end up doing a major plot one. I think the last one was 20 when you first hear of Maelstrom from James before he is turned into Urine.
If you didn't understand anything in the episode, fear not, you are not suppose to. Most of the references are just calls backs to older things and even if you got them, you are not in any better position for figuring out what just happened. This episode is simply to leave you in the dark and understand nothing except Maelstrom and the Dragon Warrior fought and the Dragon Warrior lost. If you understood that, you took everything you needed to from the episode.
If you didn't understand anything in the episode, fear not, you are not suppose to. Most of the references are just calls backs to older things and even if you got them, you are not in any better position for figuring out what just happened. This episode is simply to leave you in the dark and understand nothing except Maelstrom and the Dragon Warrior fought and the Dragon Warrior lost. If you understood that, you took everything you needed to from the episode.