For a while, it seemed like Finn was the only human in all of Adventure Time’s magical land of Ooo. That changed in the show’s second season when we met Susan Strong — although we didn’t have confirmation that the beefy woman was actually a full human until Season 3. Now, on the Islands miniseries, which follows Susan, Finn, Jake, and BMO as they look for the rest of the world’s humans, we finally know where Susan came from. It’s a sad story.
After getting separated earlier in the mini-series, Finn and Jake find Susan wandering a broken down, seemingly abandoned island that used to be a human settlement. Susan’s in a trance state, retracing her steps as her memories come back to her.
It turns out that Susan’s name is actually Kara, and she didn’t always speak in broken, Hulk-like English. We see her as a little kid training to be a seeker — the people in this somewhat dystopian society whose sole job is tracking down and stopping anybody who might want to escape to the dangerous outside world. Her teacher is Dr. Gross, a cybernetic character who first appeared in an earlier episode, while her best friend is Frieda, a young girl who is training to be a scientific experimenter.
As the two grow older (and Kara gets more buff), Frieda starts to wonder what’s beyond the island they call home. Kara at first tries to talk her out of these crazy notions — it’s her job to stop people like Finn’s dad, Martin, from escaping. However, when Frieda finally makes a break for it, Kara can’t help but assist her best friend even if it goes against everything she was taught. Just when Kara’s about to send Frieda off (or maybe even join her on the voyage), Dr. Gross intervenes, mind-controlling Kara with the cybernetic implant attached to her head.
“Target … acquired,” Kara says robotically, going after Frieda the same way she went after Finn in Season 7’s “Reboot.” Suddenly, all the weirdness with her old implant is starting to make sense.
Kara is unable to stop herself from literally crushing Frieda’s dream. It’s a difficult scene to watch, and the episode ends before we find out what happened to Frieda or how Kara escaped to Ooo to become Susan Strong. The memory, though, was enough to make present-day Susan snap back to her old self — but she doesn’t necessarily seem happy about remembering what she was forced to do.