Lilo & Stitch: The Series - Season 1 - Eps 12: Amnesio
It's Lilo's birthday, but no one has remembered. So, she decides to give herself her own party. However, during the day, Experiment #303 is activated and wipes Lilo's, Stitch's and Gantu's memory. Lilo and Gantu, who think they are Martha and Lenny go after Stitch, who has returned to his natural destructive programming, and so they think is a criminal.
About Lilo & Stitch: The Series

Title: Lilo & Stitch: The Series
First Air Date: 2003-09-20
Last Air Date: 2006-07-29
Status: Ended
Rating: 7.38/10 (from 576 votes)
Language: EN
Seasons: 2
Total Episodes: 67
Network: ABC Disney Channel
Genres: Animation, Family, Comedy, Action & Adventure, Sci-Fi & Fantasy, Kids
Production Companies: Disney Television Animation
Synopsis
This animated series chronicles the further adventures of renegade scientist Dr. Jumba Jookiba's beloved Experiment 626, who is now living happily as Lilo's alien buddy Stitch. Jumba’s remaining experiments have landed all over Hawaii in the form of dehydrated pods. Lilo and Stitch’s mission is to catch Stitch’s "cousins" before they fall into the clutches of the evil Dr. Jacques von Hamsterviel!
Cast

Daveigh Chase
Lilo Pelekai (voice)

Chris Sanders
Stitch (voice)

David Ogden Stiers
Dr. Jumba Jookiba (voice)

Kevin McDonald
Pleakley (voice)

Tia Carrere
Nani Pelekai (voice)

Kevin Michael Richardson
Captain Gantu (voice)