One of the most intricate, continuity-conscious series out there is a former Disney Channel cartoon disguised as a children's show. Gravity Falls ran for two perfect seasons between 2012 and 2016, centering around a fictional Oregon town with twin siblings, Mabel and Dipper Pines, and their great-uncle Stan. The "mystery twins" are visiting the strange Pacific Northwest town of Gravity Falls for one very long summer over the course of both seasons, helping Stan manage his storefront inside his house, affectionately dubbed the "Mystery Shack."
Despite being animated, the show's storylines carry over from episode to episode, slowly unspooling a much more complex, long form narrative than you'd expect. Plus, the show's team paid far more attention to set continuity than many others, live action or not: When something in the house in which the twins live breaks in one episode, it stays broken in later episodes. When the 'S' in the sign of "Mystery Shack" falls down early on, it remains down throughout the rest of the series.
Still, while details like this stick around, the house appears to be somewhat of a shape shifter—the retail store on the main floor appears to have more square footage in some episodes than others. It somehow contains a museum, a gift shop, and enough living space for a family of three, and for all the show's continuity care, the insides don't always look the same. Of course, for a place called the Mystery Shack, maybe this could be interpreted as intentional. Plus, if blueprints of the shack existed, they would include the dearth of hidden rooms slowly revealed throughout the series, including a secret den and an elevator hidden underground—all concealed by an inconspicuous-looking vending machine/trap door.
The series, two seasons totaling 40 episodes, is available on Hulu. Watch it with the whole family, although a handful of episodes are a little spookier than others.