It all begins with the Avengers having defeated Red Skull once again, with the Cosmic Cube in their hands and they call Red Skull out for his offscreen crimes. "The Avengers have put a stop to your dastardly deeds, Red Skull," said Thor. "Why Red Skull always choose evil," asked Hulk. "I don't know. I have a skull, it's red. My options are limited," Red Skull said as he pointed to his skull. Proud of their actions, they are not afraid to boast. "Well, once again, the Cosmic Cube is in safe hands," said Captain America. Iron Man, concerned with the Cosmic Cube's true intentions, assertively says "Careful! That thing's dangerous." Cap is not satisified with things around their town with that remark. "Why is everything dangerous nowadays? I wish we could go back to simpler times," Cap whines. The Cosmic Cube grants the Captain's wish, as it changes the Avengers team back into the late sixties and scene goes old-school style. Cap realizes that Iron Man was right about the Cube and its true nature and shouts "What the-?! We're in the 60's!" Iron Man dryly says "Well, that's just groovy. Gimme that thing, will ya? ... Man, what was our budget back then, a dollar?" Iron Man's dry comments irk Thor and he states "Why should you get to control the Cube?" "Because I can be specific," Iron Man said. "I wanna return to our time, short and sweet" The Cosmic Cube then complies to Iron Man's command to the letter as it changes the Avengers team into similar animations to the Super Hero Squad Show and the background changed to buildings. Captain America calls Iron Man out and says "You had to say "short and sweet"." Hulk then says, "Let Hulk try! Hulk know right time!" "No, no, no don't!", Cap, Iron Man and Thor plead. Unfortunately for the three it was too late - the Cosmic Cube changes the Avengers team into Adventure Time characters and the scene goes to a forest in the Land of Ooo. "I think it's fair to say we all saw this coming," Iron Man said. The quartet then see that they have changed drastically. "By Odin's beard! My hammer is now a lollipop!", Thor said. "Hulk shape has changed!", Hulk said. "And my dialogue isn't nearly as clever as it usually is," Cap says. Iron Man then says "What time is this?" The Scene goes to the title card with Hulk, Captain America and Thor holding a banner that says "With Cap, Thor, Hulk, & Iron Man" as Iron Man flies through with an enthusiastic "Wheeee!" Cap calls him out, "What have you done, Hulk?" Hulk says, "Not sure. But Hulk feel transformation coming on." "Good. Maybe Bruce Banner can shed some light on this.", Cap replies. Hulk then has his legs extended to a T. Hulk arrogantly says "Ha! Look at Hulk! Hulk can run real far! Hulk dash!", as he runsinto the forest. Iron Man asks Cap if he should bring him back to which they have an argument to which they immediately see a waffle monster. Iron Man says, "Hang on, I got this." He tries to do a Repulsor Blast but to no avail as he can only launch out glitter and rainbows and the three run away from the monster. They wound up exhausted as a little gnome hops on a tired Thor telling the trio to run in order to get away from the Ice King to which the trio mistakenly think he could help them. Ice King approaches them and asks if they brought him Princess Bubblegum to which they replied that they haven't after Cap and Iron Man get into a brief argument when Cap thought "the Bubblegum princess" was Iron Man's nickname. The Ice King then said that they were useless and freezes Cap in ice to which Iron Man commented that a situation like that happened every time. Cap then ran into the Watcher and they had the following conversation.

Captain America: What's going on?! Who are you?!

Watcher: I am the Watcher!

Captain America: What do you watch?

Watcher: Episodes of MAD, mostly. Funny show! But sometimes I catch something called Adventure Time, which is where you and your friends are now.

Captain America: That's where we are? Hmm. What else do you see?

Watcher: I see the crews of other cartoons sitting in a deli complaining about MAD like a bunch of sissies.

Captain America: Ha! They'll be sorry, because MAD probably wins an Emmy in the future, right?

(Short Silence)

Watcher: You better get back to your friends.

The conversation ends there and the captain breaks out of the ice with a hugely proud "Avengers Assemble!" Iron Nam asks what happenedand Cap says that it looks like they're in a cartoon while Hulk resurfaces repeating the last word interrogatively. "Hulk! Where hast thou been?", Thor said. "Hulk spent time with Bubblegum Princess. Should probably go home now. It's complicated.", Hulk said indifferently. However at that moment, mauraders attack and in the scuffle the Cosmic Cube is destroyed far beyond repair thus they are unable to return home. "Oh my god," Iron Man shouted. "What are we going to do now?", Cap said. The four look on as they see that they are no longer in their home while the mauraders run away in fear and awkwardness