Season
Season 4 Episode
- Season 4 William Returns
- Season 4 Double Take
- Season 4 Opening Act
- Season 4 Wreck Room
- Season 4 Skidbladnir
- Season 4 Maiden Voyage
- Season 4 Crash Course
- Season 4 Replika
- Season 4 I'd Rather Not Talk About It
- Season 4 Hot Shower
- Season 4 The Lake
- Season 4 Lost at Sea
- Season 4 Lab Rat
- Season 4 Bragging Rights
- Season 4 Dog Day Afternoon
- Season 4 A Lack of Goodwill
- Season 4 Distant Memory
- Season 4 Hard Luck
- Season 4 Guided Missile
- Season 4 Kadic Bombshell
- Season 4 Canine Conundrum
- Season 4 A Space Oddity
- Season 4 Cousins Once Removed
- Season 4 Music to Soothe The Savage Beast
- Season 4 Wrong Exposure
- Season 4 Bad Connection
- Season 4 Cold Sweat
- Season 4 Down to Earth
- Season 4 Fight to the Finish
- Season 4 Echoes
Code Lyoko - Season 4 Episode 12 Lost at Sea
7.49 23 minutes Hiroki steals Yumi's diary and Ulrich finds it. Meanwhile, in a new attempt to free William from X.A.N.A.'s evil clutches, Jeremy creates a program to find William in the Digital Sea. When he uploads the program to the Skid, the sonar becomes bugged, forcing the gang to return to Lyoko. When the Kongers interrupt their return, Yumi gets stranded, and is lost in the Digital Sea. X.A.N.A.'s attempt to take advantage of this alerts Jeremy, allowing him to direct his friends to Yumi. After fighting off the Kongers and William, who has his own ship (the Rorkal) to travel in, they return to Earth. To help Hiroki apologize to his older sister, Ulrich secretly returns the diary.
