So this show is good (for a kids show) but I really think that there is a contrast of quality and storytelling throughout the 3 seasons.
Season 1: Probably the best or second best. Siblings Mateo and Izzy discover they are " Aware Dreamers" in a magical world known as the dream world only accessible via sleep where they discover their science teacher and school friends are also aware dreamers while defeating crazy drunk guy known as the "Nightmare King". While also learning about some Lunia who has previously defeated the "Nightmare King"
Season 2: Practically same premise apart from the "Nightmare King" being replaced by the "Never Witch" to which I say never bitch. Also, a-lot of the dream work is done in the waking world.
Season3: Most recent season haven't finished it yet they have to defeat "Dream Smasher" which is a villain staging heroic deeds. It is later revealed that "Dream Smasher" is actually "Claudius" a minor villain is season 2. Then they find out that Lunia (who I mentioned earlier is "Miss Castillio" the taco lady!
So in summary great show but season 3 was unnecessary and hard to follow