After being left alone in her home, marceline begins to play a song on her bass, “Everything stays”.
As she sings we see Ooo returning to some normalcy, Bonnie becoming princess of the candy kingdom again, the “Vampire King” being a mortal lion again, Peppermint butler being put back together after being shattered, and the farmers tending to their cattle again.
And Marceline is back to her old life with some new morals and thoughts to ruminate on.