Project: Shadow (プロジェクトシャドウの謎,Purojekutoshadou no nazo?, lit. "The Puzzle of Project Shadow") is the thirty-third episode of the anime series, Sonic X, as well as the first episode of the Shadow Saga. It first aired on 16 November 2003 and 30 October 2004 in Japan and United States respectively.
The episode starts with Sonic running through the ruins of Station Square following Perfect Chaos'destruction of the city when he suddenly hears crying sounds from the debris. As the residents of Station Square repair their city, Guardian Units of Nations begins mass production of its own Hunter series robots to counter Dr. Eggman. Using a spy robot, Eggman examines their progress and notes with annoyance that "all they did was copy (his) designs." As he hacks GUN's computers for more information--displaying pictures of several GUN robots from Sonic Adventure 2--he finds a database entry for Gerald Robotnik. Eggman concludes that he was born on Earth, rather than in Sonic's world, and that the two are parallel dimensions. As Eggman continues his search, he uncovers Gerald's diary that reveals he has finished the final product of his "Ultimate Life Form" project, named "Shadow". Transferring it from GUN's computers alerts them to his activities, and the President assigns Rouge and Topaz to monitor him.
Rouge and Topaz secure a Chaos Emerald to use as bait to gain Eggman's trust--as well as the Master Emerald itself, which Rouge is unwilling to leave behind although Knuckles tried to stop her. Meanwhile, Eggman fights his way into GUN's base on Prison Island. He reaches the capsule containing Shadow and releases him, astonished to see the silhouette of a hedgehog in the cryogenic vapors.
When Chuck explains that Sonic and his friends have settled into the new home, this flashback and the next have been cut from the English dub.
Comparison of the Japanese/original (left) and English/edited (right) versions of the same scene. Note the signature.
Comparison of the Japanese/original (left) and English/edited (right) versions of the same scene. Note that G.U.N. has never been mentioned in the English version of the show and the style font of the text
Comparison of the Japanese/original (left) and English/edited (right) versions of the same scene. Note that the text on the right is entirely replaced with white dots except Shadow in the center due to the text on the left containing two swears.
Gerald Robotnik's diary was different in this episode than the one used in the source material, as it omitted any references to Maria's death or his resulting insanity, and in fact indicated that the main reason he wanted Shadow released was as vengeance against GUN for the measure of immorality he found intolerable in regards to a conspiracy involving taking over both his Artificial Chaos project as well as the Eclipse Cannon.
Knuckles doesn't recognize Rouge in her costume even though it's the same costume she wore from episode 13, "Beating Eggman, Part 2".
In the Australian DVD, the episode is simply named "Shadow".