This gets misled as the Premire as the Ninth Season. 
Finn, Jake and BMO's dreams fall under the influence of a mysterious orb.
On their way back from the islands, Finn, Jake, and BMO are going through their giant supply of bananas. BMO comments on a mysterious cloud that is following them, but Jake says to pay it no mind, and instead asks for a bedtime story. BMO starts to recite one, and the two fall asleep. Joining them, BMO makes a bed out of cloth and says goodnight to them both. Right before going into sleep mode, the cloud evaporates and reveals a mysterious orb.
Jake dreams that he is back living with his parents, in some sort of strange talk show. He finds one of his other selves, and both are aware that they are dreaming. Finn dreams that he is flying in the sky, and weaving through the clouds. BMO dreams of a world inhabited solely by BMO copies. They are producing a play about Finn and Jake, and BMO sits in the audience. In the real world, the orb draws closer.
In Jake's dream, his dad tells him and his clone to dig a hole in the floor. As they do so, a dark shadow casts over the hole. In Finn's dream, the landscape becomes stormy, and one of the clouds sprouts an eye. He sees Princess Bubblegum, and when he talks to her, she says flying is scientifically impossible. Finn finds that he can’t fly anymore, and the grass grabs onto his ankles. Princess Bubblegum's teeth fall out, and Finn screams. In BMO's dream, the slapstick goes dry, and the audience becomes bored. A rendition of BMO comes on stage, but this BMO kicks around Finn and Jake. BMO is horrified and goes to speak to the producer. The producer turns out to be the mean version of BMO, and BMO cries out.
All of a sudden, the hole Jake was digging vanishes, and he is separated from his father. He's sucked dry by a vampire, and his parents laugh at him when he cries for help. As Finn tries to put Princess Bubblegum's teeth back, he is swallowed up by the grass. He emerges in an alternate dimension, with the eye cloud looking down upon him. He hears Jake crying for help from above, and wills himself to fly. He finds Jake, shriveled and weak, but then he hears BMO criticizing the performance.
They both stand on the stage and recover instantly. All three of them realize that they are sharing the same nightmare, and an abyss opens up beneath their feet. As they fall, the eye cloud hovers nearby them. Finn grabs a dress and a pair of bat wings and attached them to the cloud. The moment he does, the cloud sprouts limbs, and they stop falling.
Finn realizes that the cloud is actually a Nightmare Princess, who entered their dreams to communicate with them. She asks for all the bananas on the ship, and BMO agrees to trade them for something "pretty and/or cool." They wake up, and the orb sucks up the remaining bananas. In return, the orb gives Finn some sort of concoction before floating away. Jake spots Ooo in the distance, but when BMO looks through the spyglass, the landscape is definitely not Ooo. Finn asks what is there, and BMO replies, "a dream."
- Snail (dream)
- Joshua (dream)
- Margaret (dream)
- Jermaine (dream)
- Banana People (dream)
- Party God (dream)
- Princess Bubblegum (dream)
- Water Nymph (dream)
- The Moon (dream)
- Warren Ampersand (dream)
- MOs (dream)
- This episode has leaked online and is available on Xfinity on Demand, Spectrum Cable on Demand, and Sling TV before its intended airdate.
- Finn is seen with both arms in his dream.
- The Kabbalah Tree of Life is depicted in Dream Joshua's house on the carpet.
- This episode has the shortest title in the series, with only three letters.
- The canned laughter used after Jermaine tells a joke is a reference to the laughter cues used in many American sitcoms such as Friends.
- The cloud with an eye, and how it gets completed with a dress and wings to transform into a full character, resembles the GROW series of flash puzzle games.
- This episode begins right where the previous episode "The Light Cloud" left off. Finn, Jake, and BMO are at sea leaving the islands and are on their way back home to the Land of Ooo.
- The main conflict of the Elements miniseries (which begins shortly after this episode's ending) is foreshadowed several times.
- The four elements of Ooo can be seen beginning to spread through the land at one point in Finn's dream. They can also be seen together while the trio falls down BMO's dream stage, and at the very end of the episode.
- When Dream Joshua makes Jake and Jermaine dig, he draws the symbol of the four elements, previously seen in "Jelly Beans Have Power."
- In his dream, Jake mentions Jermaine's house burned down in the episode "Jermaine" one year prior.
- Jake's biological parent, Warren Ampersand makes a cameo in Jake's dream. This likely is a sub-conscious truth about his birth, which was shown in "Joshua and Margaret Investigations". It is later revealed that the manner of its appearance is an actual memory, as in "The First Investigation" baby Jake sees it staring at him through the window.
- The Moon, from the Stakes miniseries, also appears in Jake's dream.
- AMO makes an appearance in BMO's dream. AMO was the main antagonist in "The More You Moe, The Moe You Know (Part II)."
- Similarly, Football, BMO's alternate persona, was mentioned.
- Bubblegum losing her teeth in Finn's dream is likely foreshadowing Finn losing his baby teeth to PB's uncle Gumbald in "Always BMO Closing".
- The MO-Lich whispering is a foreshadow of the Lich's return in '"Whispers."
- A mysterious sword appears in the title card and in the background, when Finn finds Jake in the dream play. Finn later obtains that sword in "Marcy & Hunson".
- Jake's dream where Margaret takes away his blood (and Joshua and Margaret making a strange face at him) may have some meaning in it.
- Margaret taking Jake's blood may be a truth told in a dream about her not being his birth mother, it's symbolizing that he does not have her blood.
- Joshua and Margaret make a strange smile which may symbolized that they lied to him about where he came from.
- In addition, Jake's biological parent, Warren Ampersand appears in the dream.
- This episode was screened before it had officially aired during Adventure Time Live, an event in Australia which took place through March 10th to 12th, 2017.
- This episode is considered by cartoonnetwork.com and Wikipedia to be the first episode of Season 9. It is unknown if this is true or if it is an error. According to Adam Muto, this episode along with the Adventure Time mini series Elements are a part of season 8.