Who is Fern? Fionna and Cake resurrects Adventure Time’s most tragic villain

The penultimate episode of Fionna and Cakeseason 2, “The Worm and His Orchard,” was full of reveals, including the answer to one burning question posed earlier in the season. However, the return of a certain character was perhaps the most exciting surprise for long-time Adventure Time fans. But for anyone who never finished the original series (to be fair, there are 283 episodes in total) or hasn’t rewatched it in a while, this unexpected cameo may be a bit confusing. Here’s a quick refresher course on what it all means and how Fionna and Cake picks up a loose thread from 2018.