After waking up alone and shipwrecked, Finn investigates a bizarre island in search of his friends. 
The episode begins with Finn waking up, washed up on an island's shoreline. Shortly after Finn stands up, only to find a massive wave behind him. Finn appears to be alone but he calls for Jake, Susan and BMO. Finn quickly climbs up a cliff to avoid the wave. However he is hit but it luckily does not do any damage to him and nicely goes away afterwards. After this Finn sees two crabs, he then asks them if they know where his friends are.
Finn climbs up to the top of the cliff. It appears to be very snowy at the top. There are also many elevated cabins. Finn goes inside one of them and sees seed packets and a book. Finn then walks out in warm clothing and seed packets on his face to keep warm for the snow. However it shortly warms up and all the snow melts. Finn then sees something strange and takes off the outfit.
Finn walked over to a bunch snow spots surrounded by hot desert land. Quickly the snow returned everywhere. Finn went looking for the cabin but then falls down a hill into a forest biome. There he sees an oversized mouse locked into a cage. He walks over to free it but ends up in a trap hanging from a tree. A bear than approaches Finn. Finn was not afraid of the bear at all. The bear tried to bite Finn (who was still in the trap) but Finn hit him with a stick which stopped the bear. Shortly after an old human woman walked over. The old woman told the bear (who is revealed to be her pet) to not bite Finn. The old woman did not speak any English (she spoke Swedish) she than released Finn from the tree but Finn was still caught in the trap.
Finn is then seen hanging from another tree near and camp fire where the old lady and her bear are. Finn asks the old lady if she knows where his friends are. However the old woman does not understand Finn's language and Finn cannot understand her language. The woman than walks up to Finn and takes a look at his face. The old woman appears to be the only human living on the island. The old woman took a look at Finn as she was probably surprised by the fact that he is also a human. The old woman then releases Finn from the trap completely. Finn then asks to the woman if she's seen Jake and shows her a drawing of him. The woman shakes her head implying that she has not seen him. The old lady then goes closer to Finn and points at his sketch pad. Finn then realized that she wanted him to draw her. Finn then tells her that he is not that good at drawing and he did not draw the picture of Jake. Despite this Finn happily draws her. The drawing turned out a little crude looking and the old lady did not look pleased with it.
Shortly after lightning strikes in the sky. The old lady and the bear quickly run inside the tree. Then a tornado appeared. Finn was going to warn the old woman that the place was not going to hold. However the tree is made out of metal on the inside and seems to be equipped with very harsh weather-proof technology. The old lady then went into a basement through a vault. Finn then started to figure out that the old lady does not understand him. The old lady was turning a film on and Finn asks her where everybody went to. The film has no sound and shows many humans happily thriving on the island. The old lady is seen in it but looked far younger implying that a lot of time has passed since the film was shot. It also reveals that the old lady's name is Alva. However at one point in the film the bizarre animals begin to look more threatening and the humans begin to looks nervous. This could mean that the animals went mad and killed all the humans or the humans evacuated making Alva the only human still there on the island. The film ended within a short period of time. This really disappointed Finn because he came to the conclusion that is all to know about humans. Finn also came to the conclusion that he, Alva, and Susan are probably the only humans alive. Finn then notices that the storm has ended.
Finn and Alva are seen riding on the bear in search of Jake, Susan, and BMO. They then head down to the beach that Finn washed up on where the find Jake wrestling with crabs. Jake told Finn that he does not like the island because of the crabs. Jake notices Alva and the bear. Finn tells Jake that Alva is a human herself. Finn then draws (rather crude drawings) of BMO and Susan asking if she has seen them. Alva shakes her head but draws out a map locating where they are. On the map she draws three more islands. Finn and Jake then realize that BMO and Susan must have washed up on a different island and plan to make their way there.
BMO is then seen being given a Finn cake by someone. They both appear with some sort of gamer tags above their head. BMO is seen on the moon and wishes Finn and Jake (and Susan) were there with it.
- Back to Nature Islands Humans (video)
- Giant Rat
- Giant Wolf (video)
- Susan never appears in this episode. However, she is mentioned and referred to as a giant smelly lady by Finn and he makes a rather crude drawing of her.
- Alva only speaks Swedish, and thus cannot converse with Finn and Jake. The Swedish lines in the episode loosely translate as: 
- "Stop! No, no, no, no, no! Sorry, Albert, that is not food (sigh) That sure is a weird one." (When Finn gets caught in her snare trap)
- "Don’t think I’ve seen someone like him in a long time. It’s probably a good idea to find out what he’s doing here. Come, Albert."
- "A dog?" ("Hund?", when she sees the drawing of Jake)
- "I thought it would look better" (When Finn fails to draw a sketch of her)
- "Hot! Hot! Hot!" (When she shoves her still-hot eggs in her mouth as she flees the storm)
- "Damage report number one 3/1" (printed at the beginning of her video recording)
- "The end of the film 070015" (ÄNDEN FILM)
- "The dog! No, no, not dead! My land, other lands!" (finding Jake, saying Susan isn't dead, then pointing to a hand-drawn map showing her island, then the other islands in the chain)
- Finn says "Good grief!", which is a reference to Charlie Brown.
- When Finn is sketching Alva, a small drawing of Kilroy can be seen on the bottom of the page
- Albert is similar in both appearance and behavior to the Pokémon Snorlax.
- Finn mentions Banana Guard 16 teaching him how to draw. This is a reference to "The Thin Yellow Line."
- This episode was released for digital download and DVD on January 24, 2017.