Season 1 Episode
- Season 1 Beginnings (Origins, Part 1)
- Season 1 To Catch a Queen
- Season 1 Mobodoon
- Season 1 The Price of Freedom
- Season 1 Underground Masquerade
- Season 1 Tangled Webs
- Season 1 The Deepest Fear
- Season 1 Who Do You Think You Are
- Season 1 The Last Resort
- Season 1 Come Out Wherever You Are
- Season 1 Winner Fakes All
- Season 1 A Hedgehog's Home Is Her Castle
- Season 1 Artifact
- Season 1 Bug!
- Season 1 Sonic Tonic
- Season 1 Friend or Foe?
- Season 1 Head Games
- Season 1 When in Rome...
- Season 1 The Jewel of the Crown
- Season 1 Three Hedgehogs and a Baby
- Season 1 Dunes Day
- Season 1 Mummy Dearest
- Season 1 Hedgehog in the Iron Mask
- Season 1 Six Is a Crowd
- Season 1 Flying Fortress (Chaos Emerald Crisis, Part 1)
- Season 1 Wedding Bell Blues
- Season 1 No Hedgehog Is an Island (Chaos Emerald Crisis, Part 2)
- Season 1 Getting to Know You (Origins, Part 2)
- Season 1 New Echidna in Town (Chaos Emerald Crisis, Part 3)
- Season 1 Harmony or Something (Origins, Part 3)
- Season 1 Country Crisis
- Season 1 Haircraft in Space
- Season 1 Healer
- Season 1 Sonia's Choice
- Season 1 The Big Melt
- Season 1 Sleepers
- Season 1 Bartleby the Prisoner
- Season 1 The Art of Destruction
- Season 1 The Pendant
- Season 1 Virtual Danger
Sonic Underground - Season 1 Episode 13 Artifact
6.90 25 minutes 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.
