This show deserves so much more love and attention than it currently has. It's not perfect, but it's genuinely one of the best mystery shows, best cartoons, and best overall tv shows I've ever seen.
The writing in this is absolutely phenomenal! I went into this as an adult who loves cartoons with good stories, having never seen or heard of it before, and holy cow it did not disappoint! From episode one, every single episode, and countless seemingly minor details, are all about foreshadowing a number of huge plots down the line that all fit so well as they come together.
The character are honestly so much fun both on their own and in all their interactions with others. I love that as the story progresses, more and more side characters join in on important aspects of the plot, and you get unique teamups between characters that aren't the same main three. Which, those teamups are still just as good, but it's fascinating to me that the world and characters are so well developed that each character can play their own pivotal role, merging different groups or cliques together to create unique interactions and unique solutions to problems that would have otherwise been impossible to face. It makes it feel more real than what could have been a small, forced, consistent teamup in a world where everyone is involved in the conspiracy. Detentionaire isn't afraid to show that.
Around Season 2 was when I realized just how clever the story was. Each season has it's own unique and interesting plot that is built up in every single episode. But the later seasons aren't built upon only those specific episodes. From Season 1, and even the first episode, huge plots for the rest of the show are foreshadowed in a seamless way that makes the end so much more satisfying. You can easily tell that the entire plot was conceived before the first episode was written. There are no plot points thrown in at random as the show was preparing for each season from the very beginning.
If you're not convinced after the first couple episodes, where you're hopping into a world that feels so strange and different but seems so normal to the characters, then keep watching. There are reasons for every strange creature, event, etc. That are slowly revealed throughout the series. Not to mention the show is full of funny moments, jokes, and high school experiences that make the world feel so much more vibrant and fun.
If you like shows like Gravity Falls, Over the Garden Wall, Infinity Train, The Owl House, or any shows in that vein, you'll love Detentionaire. Here's hoping the show gets a renewal one day so we can get the final season that ties everything together!