The Underground Returns is the 1st episode of Sonic Underground 2.
- Sonic (1st appearance)
- Dr. Robotnik (1st appearance)
- Sonia (1st appearance)
- Manic (1st appearance)
- Queen Aleena the Hedgehog (1st appearance)
- Sleet (1st appearance)
- Dingo (1st appearance)
- Cyrus (1st appearance)
- Pengy (1st appearance)
- Joe Sushi (1st appearance)
- Tundra Freedom Fighters (1st and only appearance)
Cyrus, a head of the main Freedom Fighters, saying the head battlers are gone, and probably captured. Freedom HQ gets attacked by Sleet and Dingo, when rubble hits their airship, with the head battlers in the Freedom Fighters come back, the Sonic Underground: Sonic, Sonia and Manic!
Sonic leads of the battle with a song called: The Underground's return! Sonic and his brother and sister, beat Sleet and Dingo, with the Tux and Joe Sushi offering them a break in the tundra, they except and later head for the Emerald Hill Zone, for a concert, Sonic begins to wonder about the Chaos Emeralds and Sonia tells them about the origin of Emeralds, telling them about the fact their are Emeralds all over the Universe and the Green Emeralds are on Mobius and that's how the Emerald Hill Zone got it's name, Sonic asks how she knows this Sonia tells her brother she learned it in the Chaos Scrolls. Tux and Sushi ask if they could join Sonic's team division and they get in the team.
For a full transcript of The Underground Returns click here.
- The Underground left Robotropolis in search of their mom with no success.
- The Chaos Emeralds existence is more detailed in this episode.