Princess Day

Synopsis
It's Princess Day in Ooo! You know what that means? Yep, LSP and Marceline team up to prank Breakfast Princess!

Plot
The episode opens up with Princesses at the Breakfast Kingdom celebrating Princess Day with Breakfast Princess being the host. She first welcomes the princesses then moves on to the princesses trading system, and how they are not getting what they want. All the princesses are arguing until Lumpy Space Princess shouts making the room quiet. LSP explains she's bored and that she doesn't want to talk about dumb stuff. Breakfast Princess then disses LSP about her home, leading to her to reveal that she wasn't invited and she is crashing. Breakfast Princess sends guards to make her leave, but LSP gobbles up a bowl of croissants before leaving without the guards touching her. Marceline sees this and decides to follow her. She invites Princess Bubblegum to join her to ditch the party but PB refuses.

Marceline catches up with LSP and tells her that she likes her attitude. Marceline decides to prank Breakfast Princess which LSP immediately accepts. The two walk around Breakfast Kingdom and find the door to Breakfast Princess' room with a guard protecting it. LSP distracts the guard and Marceline is seen drinking the Syrup from the inside of the guard. They enter the room and LSP goes to the closet and finds her clothes. Marceline looks through her music, telling Lumpy Space Princess that it's terrible, however she decides to keep one of her albums. LSP eats Breakfast Princesses clothes and the two high-five. Outside, another guard is seen walking to Breakfast Princesses room, he slowly opens the door and Marceline turns invisible. Struggling, LSP grabs a grape fruit and cuts it open. She then squirts it on the guards eyes and the two flee. They run through the hallways and LSP cuts through the pancake walls they go through while being tailed by the guard. LSP cuts a hole in the edge of the castle, the guard takes a look and the two push him down.

One of the guards tell Breakfast Princess what happened, so she leaves Strudel Princess in charge and exits the scene. LSP and Marceline are seen in a car, as they drive through, Breakfast Princess comes out of nowhere and gets hit by the car. LSP freaks out but Marceline tells her to chill. She throws the body in the trunk and drives off. Marceline and LSP (with masks on their faces) open the trunk and see Breakfast Princess. She immediately identifies LSP leading to Marceline throwing her to the floor. LSP tells her to build a sand castle with a shovel and the two drive off. Breakfast Princess drops the shovel and walks away, her fate remains unknown.

The two listen to the album Marceline took from Breakfast Princess. LSP ask Marceline if they are completely bad since they did bad stuff. Marceline tells her that good guys can do bad things, so it doesn't really matter. The two reveal they are upset about taking Breakfast Princess' album and decide to mail it to her. The two unexpectedly drive off a cliff, but they both float (with Marceline supporting LSP) and the car crashes on the ground and explodes. Strudel Princess takes over as ruler of the Breakfast Kingdom and celebrates Princess Day with everyone cheering.

Major characters

 * Marceline
 * Lumpy Space Princess
 * Breakfast Princess

Minor characters

 * Princess Bubblegum
 * Muscle Princess
 * Slime Princess
 * Raggedy Princess
 * Elbow Princess
 * Jungle Princess
 * Peanut Princess
 * Purple Princess
 * Space Angel Princess
 * Gridface Princess
 * Embryo Princess
 * Princess Princess Princess
 * Wildberry Princess
 * Hot Dog Princess
 * Emerald Princess
 * Engagement Ring Princess
 * Skeleton Princess
 * Strudel Princess
 * Turtle Princess
 * Old Lady Princess
 * Flame Princess
 * Cinnamon Bun
 * Princess Business (Mentioned)
 * Maple Guard
 * Snail

Songs

 * Breakfast Song

Trivia

 * This marked the first time Marceline and Lumpy Space Princess interact with each other.
 * It is unknown why Marceline is at the Princess Day event, since she is a queen.
 * Likewise, Cinnamon Bun is at this event even though he is not royalty, merely Flame Princess's consort.
 * Just like Wildberry Kingdom in "Furniture & Meat," Breakfast Kingdom has gone through a major renovation and is much more developed.
 * The castle is at least twice as tall, and its walls consist of bacon and stacks of pancakes instead of sausages. A bridge of bacon spans the pond created from the fountain of coffee issuing from the main percolator. A forest of orange trees surrounds the kingdom, in the midst of which is an oversize toaster.
 * It has also has changed its background surroundings. What used to be trucks and a mountain at the back of the castle has completely gone.
 * This episode marked Breakfast Princess' first major role, as well as the role of an antagonist.
 * This is the first episode (not counting the gender swap episodes) in which neither Finn nor Jake make an appearance, let alone are even mentioned.
 * Even though it is Princess Day, not every princess in the series appeared in the episode.
 * Marceline is shown holding a bottle of sunscreen in the promotional artwork and in her first appearance in the episode, which explains why she was unharmed in the morning sun.
 * This episode explains why Marceline can only eat red; she can't swallow other colors. As she explains, she physically can't digest syrup, so she vomits up the syrup she sucked out of one of the guards.  It's possible that Marceline can no longer eat regular human food (though she did eat chicken soup a thousand years ago).
 * The game Royal Ruckus takes place after Lumpy Space Princess and Marceline crash Princess Day, as explained in the beginning of the game.

Cultural references

 * The episode shares many similarities to , an American adventure film from 1991.
 * After LSP leaves the party, she cuts the wall in a similar way that did when he found out that his love interest isn't necessarily playing fair with him.

Episode connections

 * Cinnamon Bun is still an inhabitant of the Flame Kingdom and Flame Princesses consort from "Earth & Water." He might be at the event with her because of his claim to always be at her side in "The Red Throne."
 * This is Flame Princess's first appearance in a Season 6 episode, though she was mentioned several times in Breezy.
 * Old Lady Princess from "When Wedding Bells Thaw" appears at the Princess Day event.
 * Breakfast Princess first stated that Toast Princess was her sister in "Hitman," but now she stated Strudel Princess was her sister.  There might just be three Breakfast sisters, and "Breakfast Princess" is the eldest.
 * Breakfast Princesses's status report to the assembly notes that there are raiders along the west coast of Ooo, trade deficits between the kingdoms are higher than they've ever been, and that numerous unregistered princesses are proliferating across the land. This may be an explanation for why so many new princesses have been appearing in recent seasons.

Errors

 * The swivels on the left door change when Breakfast Princess calls the guards to get LSP, and when the guards entered.
 * During the scene where LSP and Breakfast Princess are arguing, Breakfast Princess is seen standing on five pancakes, but when the guards enter there are only four pancakes.
 * When LSP is kicked out, she uses a knife to cut the pancake walls. When she is complaining she is seen cutting seven pancakes, but when Marceline calls out for LSP, she is seen to cut eight.
 * After LSP mocks Breakfast Princess by calling her "Princess Egg Breath," the tables for Muscle Princess, Embryo Princess, Engagement Ring Princess, and Skeleton Princess were gone.
 * When the princesses were mocking Breakfast Princess for her "egg breath," there was no chair beside Princess Princess Princess. However, when the princesses were cheering for Strudel Princess' speech, a chair appeared beside Princess Princess Princess.
 * When Breakfast Princess says that it was a mistake that LSP was at Princess Day, Strudel Princess is behind Breakfast Princess. She is then seen sitting beside Breakfast Princess, but then when she takes over for her, she is behind Breakfast Princess.
 * When LSP and Marceline are in Breakfast Princess' room and the Maple Guard starts to open the door, the door is almost completely open when he says "I heard someone say 'where'", but when LSP goes and picks a grapefruit off the tree, the door was as if the guard had just started to open it.