It's the day of the month everyone loves. Super Porp Day (grape soda in a can). Fin, Jake, BMO and Marcy are skating and waiting at the local Squeez-E-Mart for the vending machine to be refilled with the grape soda. They begin to wonder where Super Porp comes from when Marcy says she's been drinking it since she was a little girl. Should they chase down the answer or just enjoy the soda. The refill-bots fly off and go under ground, to Susan Strong's homeland. Where suddenly a crime takes place. Susan will discover the truth!/ Jake's son T.V. discovers a mysterious diary in the dried-up moat of the Candy Kingdom, and becomes obsessed with finding out more about the writer known only as "B.P."