Morton is a random episode taking place in Season 4.
Herb's brother, Morton Pichon arrives in Kadic. Morton becomes curious about what Jeremy and his friends are up to. He also develops a crush on Yumi but Yumi doesn't return his feelings. Upon further investigation, Morton and Herb visit the factory and locate the supercomputer. While they continue to search the factory for anything else, XANA launches an attack.
A new student appears in the academy and Herb instantly recognizes the student as his brother, Morton Pichon. Morton quickly adapts to the academy and is well known, he even becomes friends with Nicholas, though Sissi treats him as a regular nerd. In Ulrich's room, someone dressed in a Ghostface costume approaches him. Thinking it's hostile, Ulrich punches Ghostface down until he takes off the mask. Ghostface is revealed as Morton, whom explains he was only making a prank on him. An embarrassed Morton convinces Ulrich to put this behind them. After this, Herb tells Morton about what they saw Odd and Aelita do at the factory and Morton suggests they pay a visit to the factory again.
At night, Herb and Morton sneak out of Kadic and get to the factory. Eventually, Herb begins to give up but Morton encourages him to go on. After using the elevator, they locate the supercomputer. The stunned nerds quickly begin examining the computer and Herb realizes that this was the real reason Odd and Aelita were at the factory. Morton advises that they don't touch the computer but instead take pictures. After taking several pictures, they leave.
The next morning, Herb and Morton sit next to the Lyoko Warriors again at lunch and show them the pictures, horrifying Jeremy. When Morton demands to know what was on the supercomputer, they refuse to tell him. Herb begins showing Sissi and Nicholas the pictures. Nicholas believes Herb while Sissi does not. he group debates what to do and Ulrich suggests a return to the past. Jeremy is reluctant to do so as it increases XANA'S power. Once the group goes they're separate ways, XANA launches an attack.
Meanwhile, Morton and Herb visit the factory again to get further proof of their discovery. They investigate the supercomputer and find the scanner room. After taking more pictures, they turn on the supercomputer and go through multiple files. Both learn about XANA and a specter appears in the room. Herb and Morton are both possessed by XANA. Herb head back to Kadic and destroys Jeremy's computer with a hammer to prevent him from knowing about the attack. Morton stays in the factory and prepares several monster for Aelita.
When Jeremy finds his computer wrecked, Herb, whom was hiding in his room, attempts to electrocute him to death. Ulrich arrives and smacks him unconscious with a flashlight. The two inform the group that the computer has been destroyed and Herb has been possessed. They then notice that Aelita is missing and Odd reveals that Herb had requested her help with technical issues. In the distance, Herb has already awakened, captured Aeila and is taking her to the factory to be dropped in the digital sea.
The group quickly tries to chase them down but Herb destroys all the skateboards and other transportation means before taking off. The group takes longer to arrive with the vehicles destroyed. When they do catch up, Morton blocks the elevator and prevents them from entering, forcing them to take the long way.
Herb manages to get Aelita into Lyoko where she is still unconscious. She is surrounded by 3 Krabs and 2 Tarantulas as they wait for William to show up. When the group gets up to the lab, Herb and Morton are waiting. Yumi is chased by Morton while the rest manage to knock out and tie up Herb. Jeremy locks down the lab by deactivating the elevator and gets Odd and Ulrich into Lyoko.
The two arrive just as William arrives on the scene. When Herb begins to awaken, Jeremy reactivates the elevator, shoves him in it and locks him inside. Meanwhile, Morton eventually catches up to Yumi and the two begin to fight hand to hand (With some similarities to Odd's fight with the possessed Delmas in Wrong Exposure). Odd manages to shoot and destroy the Krabs by staying in the air in his vehicle while Ulrich distracts the tarantulas.
William leaves the battle and begins to drag Aelita to the digital sea. Aelita finally awakens and stuns William with an energy field. While he is stunned, she helps Odd and Ulrich destroy the remaining monsters. But the last remaining monster manages to devirtualize Ulrich just before being destroyed. Meanwhile, Yumi and Morton continue to fight, ending with Yumi managing to overwhelm and beat up Morton. The fight is finished when Yumi kicks Morton in the face, knocking him unconscious. Herb finally manages to get out of the elevator and attempts again to kill Jeremy but Ulrich shows up just in time and distracts him.
Odd distracts William while Aelita fires energy blasts at him, eventually managing to defeat William. Aelita immediately enters the tower. Morton, very irritated, awakens, finds Yumi and begins to strangle her to death. In the lab, Herb begins to electrify both Ulrich and Jeremy. Aelita deactivates the tower just in time and the two brothers sink into unconsciousness.
With Jeremy's computer destroyed and the evidence Herb and Morton gathered about the supercomputer, he reluctantly launches a return to the past. This time, Herb and Morton are caught sneaking out of Kadic by Delmas, Jeremy had given them away. Embarrassed, Herb and Morton decide not to investigate and "Mind their own business".