 Japanese title card · “Assassin Shadow!” | |
| Series | Sonic X (ソニックX), TMS Entertainment |
| Season | Season 3 (2005–2006) |
| Episode | Season 3, episode 21 · no. 73 of 78 |
| English title | “The Cosmo Conspiracy” (4Kids) |
| Japanese title | 暗殺者シャドウ！ (Ansatsu-sha Shadō!, “Assassin Shadow!”) |
| Japan | Not shown on Japanese TV until 23 April 2020 (Kids Station) |
| First aired (US) | 1 April 2006 · 4Kids TV (Fox) |
| Directed by | Nana Harada |
| Written by | Masahiko Shiraishi |
| Storyboard | Nana Harada |
| Previous episode | Zelkova Strikes Back (S03E20) |
| Next episode | Eye Spy (S03E22) |
Metarex SagaShadow vs Tails
The Cosmo Conspiracy is episode 21 of Season 3 of Sonic X and the 73rd of the anime’s 78 episodes. In Japan it is called “Assassin Shadow!” (暗殺者シャドウ！). It premiered in English: 4Kids aired it on 4Kids TV (Fox) on 1 April 2006, after a French TV debut on 13 April 2005, while Japanese TV only showed it on 23 April 2020. It was directed by Nana Harada and written by Masahiko Shiraishi.
Synopsis
A few hours after the Zelkova battle, with the crew settling down to rest, Shadow slips aboard the Blue Typhoon and makes for Cosmo’s room. Sonic takes a Chaos Spear meant for Chris and is beaten down, so Tails grabs Cosmo and runs, while Amy and Cream carry the two injured friends to the medical room.
Shadow hacks the ship’s cameras to track the pair. Knuckles holds him up until Rouge appears and explains the attack: the Metarex have planted sensors in Cosmo. Shadow wrecks the X-Tornado before Tails can take off, follows them through the air ducts and beats Knuckles a second time.
Cornered, Tails pulls a lever that shoots Shadow out of the Sonic Driver, but Chaos Control brings him straight back, and Tails is badly hurt trying to hold him off. Then the Metarex appear and confirm it: Cosmo, codename White Seed, has been their eyes and ears all along. Her pendant flares, and the Blue Typhoon vanishes in a burst of white light.
Key Moments
- Shadow attacks the Blue Typhoon.
- Tails protects Cosmo.
- The Metarex reveal Cosmo’s codename, White Seed.
Trivia
- Directed and storyboarded by Nana Harada.
- On home video: the So Long, Sonic DVD set (2007); and Discotek’s Sonic X Collection 2 (2016) and complete-series Blu-rays.
Watch the Episode
The full 4Kids English episode, uploaded by TMS Entertainment’s official “Anime! on TMS” YouTube channel (checked 6 November 2026).
Part of our Sonic X Season 3 guide. See the Sonic X series page for the cast, theme songs and home video.
Sources: titles, credits and air dates from Wikipedia’s list of Sonic X episodes and Sonic Wiki Zone, cross-checked with each other and with Luke’s original Sonic Scene episode table; synopsis written for Sonic Scene from the episode, Wikipedia’s summary and Sonic Wiki Zone’s plot notes; title card and screenshots via Sonic Wiki Zone, copied to our media library.