Princess Bubblegum may be jealous when Finn starts hanging out with Flame Princess.
The episode starts when Finn finishes building Flame Princess' new house, which Flame Princess loves. A small fire spreads to Finn's feet, which he says doesn't hurt as much as it used to, but the fire accidentally spreads to the rest of his leg and he screams, then runs in a panic towards a nearby lake. Flame Princess and Jake then rush to the side of the cliff and look at the water to see if Finn is alright. After doing some tricks that Flame Princess and Jake think are funny, Jake pulls him back up on land. Flame Princess thanks Finn for building her new home. Finn and Flame Princess try to hug, but they're interrupted by Jake, who knows that they would/might hurt each other. Jake wraps Finn in tin foil and when he is finished, Finn and Flame Princess hug. They let go after a while, and then Finn and Jake walk away into the forest, saying goodbye to her.
Finn didn't know if a hug was okay and asks Jake for tips. Jakes advice is to "let things take their natural path" and explains some "junk" about dating. He creates "tiers" or a set of stairs from his hand and then explains that Finn is, "at Tier 1, which is hugging, but pretty soon, you'll be at Tier 2, which is smoochin'. Jake then explains about the rest of the tiers using references that would apply to Lady Rainicorn. He then tells to Finn that he needs a shower because he smells. The two enter the treehouse, to see PB has broken in to collect taxes. Finn then tells PB to "not inhale" while he goes up a ladder to take a shower. Jake then reveals to PB that he's hanging out with Flame Princess. Princess Bubblegum is distraught from this, and quickly runs-off, forgetting the taxes. Jake is confused, but is interupted by a video chat. The next day, as Finn is going to leave to hang-out with Flame Princess, he is stopped when PB is standing in the doorway. She then attempts to explain to the duo why Finn can't see Flame Princess, but in the process, Finn leaves and Jake falls asleep. Princess Bubblegum then thinks that Jake understands what she said, but he wasn't listening to PB and then thinks that she's really jealous of Finn and Flame Princess.
Later, Finn returns from his date with FP, not accomplishing Tier 2. Finn asks what PB was talking about and Jake tells him that she's jealous of Finn and FP, which makes Finn frown. Jake then tells Finn that the best way to get to Tier 2 is with a "sappy poem". So he helps Finn write one, but as Finn is explaining is feelings toward Flame Princess and how she makes him feel, Jake falls asleep again. Finn is seen later at a hill at sunrise trying to gain inspiration for the poem, which succeeds when the sun comes up, then Princess Bubblegum shows up and asks if Jake explained why he can't see Flame Princess anymore. Finn retaliates by saying that he loved her, but she didn't love him back. And now that he's ready to move on, she now comes and tries to get him to fall in love with her again and that he won't let her ruin everything, so Finn leaves, a clearly confused PB picks up one of the scraps of paper Finn wrote on and quietly exclaims "Oh, no!". Jake is seen later making and singing Pancakes, when Princess Bubblegum appears again and asks Jake in Finn is with Flame Princess, and Jake says that that's his "man biz". When she continues to pry at the subject, Jake retaliates by yelling at her. Princess Bubblegum explains that Flame Princess's elemental matrix can't handle extreme romance, and that when she does, she will burn through the Earth's crust and core, destroying it from the inside. Princess Bubblegum then says that's why she was locked inside the lamp, to contain her.
The two rush over to Flame Princess's new home, where the Finn is reciting his poem to Flame Princess, but midway through, it gets burned to ashes, which brings laughter to the two, and afterward, they kiss. Flame Princess then burns very, very brightly, explodes, and starts burning a hole through the Earth's crust. Finn (who appears to have been injured due to the kiss because his lips and parts of his face are burned) grabs one of Jake's arms, ties it around himself, and then jumps into the hole after FP. Jakes struggles with the weight and falls on the hole, sealing it. PB says that Jake is depriving Flame Princess of oxygen and so she will burn out, which will stop the process. Finn reaches Flame Princess and he sees that she has passed out and turned into a very weak shade of blue. Finn (struggaling to breathe) says that she is not going to die and he kisses her and gives her air, which awakens, and rekindles and stablizes her, though it causes Finn to pass out. Jake pulls the two up. Finn (who appears to be even more burned) awakens and asks FP if she is okay. Finn then kisses a rock, and holds it out to Flame Princess who also kisses the rock to symbolize them "kissing." The two walk off, and as this happens Princess Bubblegum sighs sadly and whispers "Oh, Finn." She turns around and sees Jake staring at her and he asks if she's jealous, which she replies, "Shut up."
- Princess Bubblegum
- Flame Princess
- Flame King (Mentioned)
- Tree Trunks (In Jake's Dream)
- Lady Rainicorn (Indirectly Mentioned)
- When Finn put out the fire on his foot it didn't hurt Flame Princess because it wasn't a part of her anymore.
- This marks Flame Princess' third appearance in the series and her second appearance in the fourth season so far.
- When Jake explains the tiers to Finn, he's talking about his and Lady Rainicorn's relationship.
- This is the first time Finn kisses a princess his age, as opposed to a princess who is biologically his age, but still technically older, as was the case with Princess Bubblegum in "Too Young".
- Princess Bubblegum says she told Flame King to lock up Flame Princess because she was physically unstable and could destroy the world from the inside.
- The Promo art shows Princess Bubblegum with a crying Flame Princess who is locked up.
- Finn kisses Flame Princess three times with the last kiss being an indirect one through a rock.
- This is the first time when Finn let out his feelings about Princess Bubblegum to her.
- This is the second time The Morrow has appeared.
- Jake dreams of being the President. Tree Trunks can be seen in the dream.
- When Finn is outside at sunrise, if you look closely, you can see a dot above a giant cloud on the right.
- When Jake was drawing in the mud at the beginning of the episode, he was drawing Lady Rainicorn.
- This is the second time Finn gives mouth-to-mouth CPR. First being "The Jiggler."
- Some of the formulas on PB's sciency information include:
- y = mx + b + c which is the formula for the slope of a line but the "+ c" is superfluous.
- A picture of the Earth with the crater can be seen on Princess Bubblegum's holo-screen, when she is trying to explain why Finn and Flame Princess can't see each other.
- FINN + LOVE + FLAME PRINCESS
- It's revealed that Finn and Jake pay taxes to keep their Tree Fort.
- The title card is a reversal of the title card for "Incendium." Finn is crying with photos of Princess Bubblegum in Incendium, while it is reversed in Burning Low with Princess Bubblegum crying with photos of Finn.
- Jake acknowledges how much Princess Bubblegum hurt Finn back in "Incendium."
- This is the second time Flame Princess burned out. The first time was Incendium.
- The music that was played on BMO was used in a title card for a past episode.
- When Jake is cooking the front right burner of the stove is on, but when he turns around to talk to Princess Bubblegum, the front left burner is on.