Sonic Underground: 1x13
Artifact
The Hedgehogs steal historical artifacts of Mobuis from Robotnik before he can pawn them off at an auction. Sonic and Sonia take one of the pieces to a university professor who informs them that the artifact is actually a bomb from the Mobian war. The Hedgehogs must act fast to retrieve the bomb and protect the treasure that is the key to Mobius past.
1 - 1Beginnings (Origins, Part 1) Aug. 30, 1999- 1 - 2To Catch a Queen Aug. 31, 1999
- 1 - 3Mobodoon Sep. 01, 1999
- 1 - 4The Price of Freedom Sep. 02, 1999
- 1 - 5Underground Masquerade Sep. 03, 1999
- 1 - 6Tangled Webs Sep. 06, 1999
- 1 - 7The Deepest Fear Sep. 07, 1999
- 1 - 8Who Do You Think You Are Sep. 08, 1999
- 1 - 9The Last Resort Sep. 09, 1999
- 1 - 10Come Out Wherever You Are Sep. 10, 1999
- 1 - 11Winner Fakes All Sep. 13, 1999
- 1 - 12A Hedgehog's Home Is Her Castle Sep. 14, 1999
- 1 - 13Artifact Sep. 15, 1999
- 1 - 14Bug! Sep. 16, 1999
- 1 - 15Sonic Tonic Sep. 17, 1999
- 1 - 16Friend or Foe? Sep. 20, 1999
- 1 - 17Head Games Sep. 21, 1999
- 1 - 18When in Rome... Sep. 22, 1999
- 1 - 19The Jewel of the Crown Sep. 23, 1999
- 1 - 20Three Hedgehogs and a Baby Sep. 24, 1999
- 1 - 21Dunes Day Sep. 27, 1999
- 1 - 22Mummy Dearest Sep. 28, 1999
- 1 - 23Hedgehog in the Iron Mask Sep. 29, 1999
- 1 - 24Six Is a Crowd Sep. 30, 1999
- 1 - 25Flying Fortress (Chaos Emerald Crisis, Part 1) Oct. 01, 1999
- 1 - 26Wedding Bell Blues Oct. 04, 1999
- 1 - 27No Hedgehog Is an Island (Chaos Emerald Crisis, Part 2) Oct. 05, 1999
- 1 - 28Getting to Know You (Origins, Part 2) Oct. 06, 1999
- 1 - 29New Echidna in Town (Chaos Emerald Crisis, Part 3) Oct. 07, 1999
- 1 - 30Harmony or Something (Origins, Part 3) Oct. 08, 1999
- 1 - 31Country Crisis Oct. 11, 1999
- 1 - 32Haircraft in Space Oct. 12, 1999
- 1 - 33Healer Oct. 13, 1999
- 1 - 34Sonia's Choice Oct. 14, 1999
- 1 - 35The Big Melt Oct. 15, 1999
- 1 - 36Sleepers Oct. 18, 1999
- 1 - 37Bartleby the Prisoner Oct. 19, 1999
- 1 - 38The Art of Destruction Oct. 20, 1999
- 1 - 39The Pendant Oct. 21, 1999
- 1 - 40Virtual Danger Oct. 22, 1999