"President Porpoise is Missing!" is the eighteenth episode in the seventh season of Adventure Time. It is the two hundred nineteenth episode overall.
The episode opens with Finn and Jake playing a video game on BMO, only to be interrupted at a crucial moment in the game by an emergency alert that President Porpoise is missing. Finn doubts President Porpoise's existence but BMO and Jake confirm that he is real, and that they video chat sometimes, so they agree to tackle the mystery. Finn suggests going to Banana Man's house to ask to borrow his submarine, only to find Banana Man is already in the house, secretly watching them from behind a couch. He explains that sometimes he gets lonely and needs to hear the sound of other people's voices, and that they can borrow his submarine on the condition that he gets to pilot it. BMO wants to join the trek, as does the Ice King, who was also secretly watching them and was invisible the entire time. Finn asks if anyone else is there and wants to go, which is met with silence. After the five leave, Marceline, Starchy, Crunchy, Princess Bubblegum and Gumdrop Lass emerge and get cozy in the Tree Fort.
Banana Man makes Finn the first mate and Jake the morale officer. BMO, on the other hand, is given a special task to stay behind and distract Ice King while they go down, as not to risk him interfering with the Fish Parliament. Ice King attempts to run after them, but BMO distracts Ice King with a role-playing submarine adventure of their own, with BMO as captain and Ice King as lieutenant.
In the submarine, Jake suffers severe claustrophobia and shrinks down, getting himself stuck in a series of cracks. Banana Man asks Finn to help him calibrate the wind-shield wiper fluid valve, but Finn is too distracted by Jake and Banana Men is left to handle this himself.
At the Fish Parliament, Secretary Octopus announces that Vice President Blowfish will be serving as acting president in President Porpoise's absence, but he opposes him being sworn in as the new president. Finn, Jake and Banana Man burst through a wall in their submarine and announce that they are there to help.
Meanwhile, BMO and Ice King are still role-playing. BMO announces that their submarine is running out of oxygen and needs to surface, but Ice King fears that the enemy will see them if they surface now.
Back at the Parliament, Vice President Blowfish is agitated by Finn and Jake's intervention because they are not fish, only for them to point out that they are mammals, like President Porpoise. The Parliament holds a vote to determine whether Finn's and Jake's help is wanted. All but Secretary Octopus and Representative Cybil say no, but Sec. Octopus raises all eight of his arms, giving the "yes" vote a 9-8 majority. Finn and Jake are given 20 minutes before 5 o'clock to find President Porpoise, when VP Blowfish will be legally sworn in as new president. Blowfish suddenly calls for Finn and Jake to hold a 20-minute presentation and is called out by Jake for his suspicious activity.
In their role-playing adventure, BMO plays the part of a caring yet strict leader and Ice King being a father who wants to see his kids. BMO assures Ice King that he always "gets his boys home".
Finn suspects that Blowfish is responsible for the disappearance. Banana Man announces that he is going out to look for the President, but no one pays him mind. He sits outside and ponders why is bad at speaking to others. Cybil comes outside, kisses his helmet and leads him down a gully where he begins to sing "Two Halves Make a Whole". Over this musical sequence, BMO and Ice King are being shot at by imaginary enemies, Jake tackles Vice President Blowfish, and Banana Man dances with Cybil. Banana Man says that he should get back to finding President Porpoise, but Cybil doesn't care, as national politics aren't in her interest.
At 5 o'clock, President Porpoise suddenly returns and reveals that he had simply taken a three-day weekend. Secretary Octopus looks at his arm and remembers that he had tied a string around it to remind himself about that weekend, as Jake makes a pun about blowing up someone's ego in response to the Parliament not wanting them to tell anyone above about the little confusion held undersea.
Jake worries about where Banana Man is, as the oxygen is getting low in the submarine. Finn and Jake get a face-full of water as they laugh it off and enjoy each other's company, while Banana Man and Cybil are near the surface, enjoying the sunset.
- Ice King
- President Porpoise
- Sea Creatures
- Princess Bubblegum (cameo)
- Marceline Abadeer (cameo)
- Starchy (cameo)
- Crunchy (cameo)
- Gumdrop Lass 1 (cameo)
- Banana Man's yellow submarine may be a reference to The Beatles' "Yellow Submarine".
- The symbol on President Porpoise's laptop resembles the logo of Apple Inc. It also resembles a symbol on a fez of Gravity Falls character Grunkle Stan.
- President Porpoise makes his formal appearance in this episode, after previously having been seen on BMO's screen for a video call to Jake in "Burning Low".
- Banana Man makes his first major appearance since "We Fixed a Truck", and is still eager about his friendship with Finn and Jake.
- This episode leaked online before its intended airdate.