“Mysterious Island” is the third part of the Adventure Time mini-series Islands and the ninth episode in the eighth season of Adventure Time. It is the two hundred fourty-seventh episode overall.
Adventure Time with Finn Jake Season 8 Episode 9
After an encounter with a colossus, Finn wakes up on an island where the weather drastically fluctuates. He encounters an old lady named Alva (voiced by Helena Mattsson) who does not speak English. Alva invites Finn to her home and shows her home movies of other humans who have presumably died. Later Finn, Alva and her pet bear encounter Jake who does not know the whereabouts of BMO and Susan. On the moon, BMO is being attended to by another robot and wishes that Finn, Jake and Susan could join her.