Mad Space is the twelth level in the Dark Story of Sonic Adventure 2 and Rouge's final stage. This stage's background music is 34°N, 23°E, with Tabitha Fair as the vocalist. It is equivalent to Knuckles' stage, Meteor Herd.
Rouge hears that Sonic and the others have escaped, so she tricks Eggman into giving her the password for the space colony control, gaining access to the Project: Shadow files. After finding them, she sees Knuckles has lost the Master Emerald shards, she goes after them. Rouge sets out to the outer perimeter of the Space Colony ARK to retrieve the rest of the Master Emerald Shards and flee the ARK. she finds three and is then confronted by Knuckles who she then fights. After their fight, Rouge runs to Knuckles in an attack. Rouge slips and falls towards a lava-like substance. Knuckles (claiming he only did this for the Master Emerald), caught Rouge's hand and pulls her up. Rouge pulls her hand away and gives Knuckles the rest of the Shards. Knuckles apologizes for hurting Rouge and runs off.
Rouge's Iron Boots upgade is located in this stage on the spherical planet. It will allow her to break steel containers.
- The hints in Mad Space are different from those that are in other treasure hunting stages.The first hint is completely backwards being only readable when one read the letters backwards. The last two are shown written regularly, but tell exact opposite location of where the emerald actually is.