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 23 Hedgehog in the Iron Mask
6.90 25 minutes The Hedgehogs latest quest to find their mother takes them to the prison tower where they encounter a masked stranger who insists he is family. This stranger is actually being used as bait for another attempt by Robotnik to capture them. The stranger creates a rift between the siblings, which leaves the Underground disbanded, vulnerable and ultimately trapped.
