Misery Zone (jokingly referred to in-story as the Missing Zone) is a Zone on Mobius far away from any other. It was originally said to be isolated and impossible to escape from, although it was later discovered to just be out of the way. The Zone once contained hundreds of deadly monsters, imprisoned so that they cannot harm the peaceful residents on the planet. Unfortunately (for them), one monster accidentally destroyed the entire Zone, erasing all life in the area.
At some point in this rule of Mobius, Doctor Robotnik discovered the Misery Zone and that it contained many evil beasts. The tyrant concocted a plan that would trap Sonic the Hedgehog in this inescapable land while simultaneously unleashing the Zone's deadliest monster on the Emerald Hill Zone. To this end, Robotnik created the Inter-Zone Exchanger and tasked The Mysterious Traveller with delivering it to Emerald Hill. Sonic and Tails soon arrived on the scene to greet this stranger but Sonic saw right through his disguise, instantly condemning him as a lackey of Robotnik. Tails, on the other hand, was too distracted by the thought of "mega-coolness" that the device promised and found himself in the dark and unhappy Misery Zone. Once there, Tails realised he was out of his depth and attempted to evade the monsters while thinking of a way out. Fortunately, Sonic found a way to reverse the situation and brought Tails home, sending the "Unbeatable Foe" back to the Misery Zone just as it unleashed its "Apocalypse Blast". The subsequent attack utterly destroyed the Zone and all life on it.
It would later be discovered that the Misery Zone survived, yet was now completely deserted. Commander Brutus used the Zone as a base of operations and the final destinations for Mobians set to become organic batteries for his new Badniks. From here, he launched an offensive on Johnny Lightfoot as well as plotting his revolution against Robotnik. Once the Trooper was defeated, the Misery Zone base was either abandoned or taken over by Robotnik.