While on a cruise ship, Timon and Pumbaa fight over who should be captain, and accidentally set the ship in motion.
"Going Over-Boar'd" begins by introducing Timon, a meerkat, and his warthog friend, Pumbaa. At the start of the episode, Timon and Pumbaa are on a cruise ship sitting on sun chairs. The two then fight over who could be captain if they knew how to control the boat.
Captain Quint comes to Timon and Pumbaa for the two to show him their tickets, which they don't have, leading to Timon trying to create a distraction while he tries to get Pumbaa to run. After realizing that Timon and Pumbaa are stowaways, Quint has one of the crew secure the two friends so they won't get into trouble, that way he can deal with them after dinner.
Captain Quint's assistant takes Timon and Pumbaa to a room. Timon tricks him into letting him in first in order to lock him in so they can escape. After they succeed, they hide in the captain's room and see that the captain isn't driving the boat. Timon takes the captain's hat and plays with the wheel. Pumbaa wants to be captain too, but Timon won't let him because there's only one captain and that he needs to know about all sorts of nautical things, the direction he needs to go, and that he needs to wear a hat.
Timon then sees that the boat is about to go on a desert island. He tries getting help but no one answers. The meerkat then turns the wheel and the boat turns around. After Timon's success of getting the boat to turn, Pumbaa gets an idea to trick Timon into thinking that someone called him. When Timon talks on the phone, Pumbaa takes the hat and drives the ship while Timon realizes he got tricked.
Pumbaa sees that the boat is about to run into an octopus. After the boat "shaves" the octopus' head, Timon takes the hat from Pumbaa and then the two start fighting over who should be captain and which way they should go, accidentally setting the ship in motion.
Timon and Pumbaa later see a big wave going after them. When they see that they're going to the end of a road, Pumbaa pushes a lever that causes the boat jumps from one road to another while the wave falls down.
After Timon and Pumbaa escape the wave, Pumbaa takes the hat from Timon and then sees that the ship is falling off the cliff. The boat hits the octopus and the octopus goes after it, grabs the ship (and Captain Quint, who has been realizing that someone was controlling his boat while he was about to eat his dinner), and goes underwater with it. Seeing that water is coming inside the ship, Pumbaa takes an inflated female octopus out of the boat to distract the octopus while the boat gets out of the water.
An enraged Captain Quint goes to his room and sees that Timon and Pumbaa have been controlling his ship. The boat then hits an ice cube, causing the ship to sinks. Timon, Pumbaa, and Quint are now on a small boat and watch the titanic sink. When Timon and Pumbaa tell Quint that he is supposed to go down with the ship since he's the captain, he gets mad and puts Timon and Pumbaa on a raft.
While Timon and Pumbaa on the raft, the two once again fight over who should be captain and which way they should go.