When another plague of Candy Zombies arises and Princess Bubblegum is among the undead, Finn and his friends are in a race against time to figure out how to stop it... but things get worse by the minute.
The episode begins with Finn, Jake, Lady Rainicorn, and Lumpy Space Princess running from Candy Zombies and just barely escaping to the Castle in the Candy Kingdom. They see Princess Bubblegum, and are informed that while she was experimenting with candy zombie tissue, Cinnamon Bun ate it and then infected the entire Candy Kingdom while Princess Bubblegum escaped.
She is coming up with a cure, but a candy zombie bursts through the window and bites her on the shoulder. She tells Finn to use Science but, before she can explain, she is turned into a zombie. All she could manage to say was: "Just Let Science do the work! Science...is... MUHRAAHH!" Lumpy Space Princess then pushes Finn away from the window and hits zombie Princess Bubblegum with a board and nails the board to the window.
Finn says they will have to make their own formulas to cure the Candy Kingdom. Finn tests his cure on a candy zombie but with horrible results. The candy zombie grows wings and infects the other zombies with the same liquid giving them wings as well.
There is a view of Starchie on top of a building stating that he is glad he is not down there with all the zombies to get infected and starts to do a little dance, but is grabbed by Pineapple Guy and thrown into the window and breaks through the wood.
Finn and the rest of the group escape to the top of the castle to continue to try and cure the zombies. Lumpy Space Princess then drops her formula on to some of the zombies, and it does nothing but give them enlarged lips. Lumpy Space Princess wants this to happen, goes outside to lick it up, and ends up getting turned into a zombie herself. Jake and Lady Rainicorn then test their formula, but it only makes the zombies stronger. The candy zombies use their new abilities to reach the top of the castle and attempt to bite the group, so they retreat to the lab. The zombie Candy Cane Guy comes out from hiding in the lab and bites Jake, who uses his Stretchy Powers to prolong the effects. However, Jake realizes he will become a zombie, so he goes into a sealed science shower and soon turns into one. Lady Rainicorn feels sorry for him, and lets Jake out, only to be bitten. Then, the candy zombies break through to the lab, and Finn locks himself in the science shower. He then apologizes to everyone and finds it funny he doesn't know who Science is. When Science points to the label that has its name, Finn realizes that Science is Princess Bubblegum's rat. Science creates the antidote and Finn tests it on Jake, discovering that it works, but then Jake gets attacked by the mob of Candy zombies that were standing by him. Finn covers himself with the antidote, and the crowd of zombies break into the science shower.
- Candy People
- The safety shower in Princess Bubblegum's lab is actually labeled "Sciencey Shower."
- There is a Scientific Parasite in Princess Bubblegum's lab coat pocket, the same that was in her purse at the beginning of "Susan Strong."
- When Jake is being re-zombified and then attacked by the candy zombies after Science makes the decorpsinator serum, some of the music from the title card of "Death in Bloom" plays.
- The formula for the decorpsinator serum begins with the number "4," which was the missing element to her previous decorpsinator serum in "Slumber Party Panic."
- In this episode the decorpsinator serum is yellow-green, but in "Slumber Party Panic" it was orange; even though they are supposedly made using the same formula. Also, one of the main ingredients is "Knife Juice."
- When Princess Bubblegum said "Science is muhraahh," she was attempting to say "Science is my rat."
- The plague is caused by Cinnamon Bun eating the zombie flesh. However, in "Slumber Party Panic" when the Candy People ate the candy from inside the zombies they were unaffected.
- In Princess Bubblegum's flashback, there is a laser pointed at a chair and a pile of bones on the floor.
- The only time a full zombie transformation appears onscreen is when Jake is bitten for the second time.
- Jake tells Lady Rainicorn he can stretch forever although he could not in "The Limit." However, this may have just been his way of calming her down.
- The background music played when Finn, Jake, Lady Rainicorn & Lumpy Space Princess were making the serum was the same in "Dad's Dungeon" when they were chasing the sparkles.
- Along with "The Creeps," this episode aired as part of Cartoon Network's 2011 Halloween programming event.
- A few minutes of this episode were previewed at the Adventure Time/Regular Show panel at New York Comic Con 2011.
- Background artist Santino Lascano's wedding date (8/18/12) appears twice in this episode.
- On the top of Lumpy Space Princess' de-corpsinator serum sheet, it states, "hotmail? what is it?"
- When Princess Bubblegum is giving awards, Finn didn't get a medal, although Finn got the idea to soak himself with the decorpsinator and let the zombies bite him.
- This episode involves the candy zombie plague that first appeared in "Slumber Party Panic."
- Science's cage is labeled "TS-19." This is probably a reference to The Walking Dead series in which "TS-19" is the title to the last episode of the show's first season, during which a test subject, "TS-19," reveals crucial information about the zombie infestation to the group.
- The scene where Finn is locked in the Sciencey Shower with the antidote could possibly reference to the film "I Am Legend" when Robert Neville is locked in a glass room with the infected trying to break in, also with an antidote.
- A blue-colored Scorpio symbol can be seen in the background inside one of the Candy Castle's rooms, a possible reference to the popular webcomic Homestuck.
- Jake's possesed arm could be a reference to Evil Dead II, as the show runners have previously shown their fondness of the franchise in Slumber Party Panic when Army of Darkness is referenced.
- Candy Cane Guy has regular arms when Jake pushes him into the locker, yet when he escapes he has strong-arms. Later, in another scene he has normal arms again.
- Lumpy Space Princess is not holding a nail when she boards up the window; she just begins hammering the board and a nail appears.
- When Jake was bitten after Finn poured the antidote on him, the outside of Jake's eyes are black, and then when he is seen again, they are all green.
- When all the Candy Zombies are in the science room, and Finn is in the "Sciencey Shower," as it zooms out, the zombies' wings are gone.
- The second time Jake is bitten, he does not have Gigantic Lips, Strong arms and Wings, even though the Candy Zombies that bite him have those.
- When Jake and Lady finish their antidote, it is in a test tube, but it is in a round bottle when he pours it out.
- In Princess Bubblegum's flashback, the shower is labelled "Safety Shower." Later in the episode, however, it has the words "Sciencey Shower."
- When Finn puts Science's tank underneath the lab table it is only just fits. Each time the table is shown after this it grows slightly until it is easily double the height, possibly to make Finn taking her out of the tank easier to animate.