Lumpy Space Princess meets an old classmate from high school and falls in love, which he reciprocates. However when he has to do a business meeting with Princess Bubblegum, LSP flies into jealousy leading to tragic consequences.
- Absentee Actor: Finn just has a silent cameo.
- Bait-and-Switch: After LSP gives a moving monologue about how giving up the one you love is a great sacrifice and she's not sure if she can be that kind of person, she lights a rag in the neck of the bottle she's holding and throws it through the window of the Candy Castle, then drives a truck through the door.
- Black Comedy: Princess Bubblegum's revelation that she has cyanide gum under her conference table.
- Bowdlerise: Some countries censored LSP using a petrol bomb.
- Continuity Nod:
- A Mud Scamp from "The Hard Easy" reappears in the episode.
- The miniature candy people PB experimented on in "The Lich" reappear, still being used as experimental subjects.
- Jake mentions the events of "Betty" in the opening scene to explain why he isn't impressed by PB's time machine.
- Downer Ending: LSP tries to use the time machine to "fix" her relationship. But due to the way Bubblegum's machine works, she winds up phasing Johnny out of existence. What makes it worse is that due to the way the episode was made, we actually see where Johnny ends up and he watches as LSP request Bubblegum to use the machine so she won't remember him.
- I'm Crying, but I Don't Know Why: Even after PB erases LSP's memories of Johnny she's still cryingnote , but doesn't know why she's crying.
- I Need a Freaking Drink: PB, drinking alone after realizing her invention has been used to phase Johnny out of existence.
- Insistent Terminology: Princess Bubblegum insists that what she's made is a time machine, even though Jake points out that all it really does is "move stuff around".
- Lethally Stupid: LSP accidentally erases Johnny from existence after trying to use the time machine when she had no understanding of how it worked.
- Molotov Cocktail: Lumpy Space Princess throws a root-beer Molotov through a window of Bubblegum's castle. LSP then pulls the brakes out of a nearby fuel tanker and sends it hurtling towards the castle doors for an almighty explosion.
- Poor Communication Kills: Due to LSP's usual Drama Queen antics, she assumes the worst when Johnny states he had to go to a dinner with Bubblegum, when it was just simply a friendly business transaction and nothing more.
- Unexpectedly Dark Episode: Even by the standards of the darker episodes of Adventure Time, this one is grim.
- Void Between the Worlds: The whole episode shows the events occurring in a circular iris surrounded by another space with cartoon entities frolicking. After LSP erases Johnny, he reappears alive in this outer zone, apparently aware of what happens inside it but unable to interact.