Sonic Underground - Season 1 - Eps 18: When in Rome...
Sonic becomes frustrated that maybe all of their efforts of fighting for freedom seem futile. Sonia suggests that they go to Oracle, the spiritual guide, to put everything into perspective. The Oracle makes a deal with the Hedgehogs, stating that if they can complete this next mission, he will reveal their future. Instead upon arrival in the ancient city, they discover their power medallions are missing and they are powerless.
About Sonic Underground

Title: Sonic Underground
First Air Date: 1999-08-30
Last Air Date: 1999-10-22
Status: Ended
Rating: 6.9/10 (from 145 votes)
Language: EN
Seasons: 2
Total Episodes: 40
Network: TF1 Syndication
Genres: Action & Adventure, Animation, Kids
Production Companies: Les Studios Tex SARL, DiC Entertainment, TF1
Synopsis
Sonic, Sonia, and Manic are the children of Queen Aleena Hedgehog, the rightful ruler of Mobius, and are pursued relentlessly by Doctor Robotnik and his bumbling bounty hunters sidekicks, Sleet and Dingo. As infants, the siblings were separated and placed in hiding to fulfill a prophecy made by the Oracle of Delphius that the triplets would grow up to find their estranged mother, overthrow Robotnik, and take their places once more as Mobius' rightful rulers.
Cast

Jaleel White
Sonic / Manic / Sonia (voice)

Garry Chalk
Dr. Robotnik (voice)

Maurice LaMarche
Sleet (voice)

Peter Wilds
Dingo (voice)

Gail Webster
Queen Aleena (voice)

Ian James Corlett
Cyrus (voice)

Sam Vincent
Sonic (singing voice)

Tyley Ross
Manic (singing voice)

Stevie Vallance
Sonia (singing voice)