Finn, Jake, and Lumpy Space Princess (LSP) enter Lumpy Space to find an antidote for Jake, who is turning lumpy. LSP's parents, particularly her father, question her bringing 'smooth people' into their domain. LSP is trying to help Finn and Jake and insists they don't 'lump at her'.

LSP's mother confiscates her car keys after LSP makes her cry, banning her from using the royal car. This prevents them from easily reaching 'Make Out Point' where the antidote is located, forcing LSP to seek an alternate ride.

LSP calls her friend Melissa, who is dating LSP's ex-boyfriend Brad, to ask for a ride. Melissa is preoccupied with arrangements for the weekly Promcoming dance, making the request for a ride to 'Make Out Point' more complicated.

Melissa drives them to what they believe is 'Make Out Point'. During the ride, Finn expresses concern over Jake's worsening lumping. Jake, in turn, asks Finn to bury him under the 'nicest, shiniest tree' if he fully transforms.

They arrive at what turns out to be Brad's hat, not 'Make Out Point'. Melissa, wanting to make out with Brad, intentionally took them to the wrong location, creating further delays in their search for the antidote. This causes romantic tension and a humorous struggle for LSP.

As they finally approach the real 'Make Out Point', LSP warns Finn about the people who use the antidote there, describing them as 'smooth posers'. She urges them to hurry and get the antidote to help Jake before further complications arise.