This Era immediately follows the Split Mountain Era. The humans are forced to search for a new refuge to protect them from the robots, even though they won the Striking Venom Attack, they were severely crippled and the Sentai Fortress is ruined. The robots continue attacking the humans and begin to claim the lower parts of the Northern half of the Sentai Mountain. Sensei Keiken sends three of his four best pilots, Hikaru, Takeshi, and Ryo to search for a mythical Golden City he had heard of. So the three pilots travel up the side of the mountain, and after several attacks by the robots using new battle machines, including Iron Condors, Shadow Crawlers, and Claw Crushers, they manage to find the city, but at a cost. All three of the human battle machines circuitry is fried, and they have to seek refuge in the golden city immediatly. While they are inside, they discover three new battle machines, The Blade Titan, The Sky Guardian, and The Cyclone Defender.
After this the rest of the exo-force team migrates to the Golden City, and Ha-Ya-To (the fourth of the best pilots that was left behind), manages to find his own battle machine, The Golden Guardian, which helps the humans greatly in their battles against the robots. They also discover another code that unlocks four more Golden Guardians hidden in the city, and soon after the robots unleash their largest attack yet, The Golden City Attack, using the newest and largest robot battle machine ever, The Mobile Devastator.
During this attack the humans find out that their leader, Sensei Keiken, had been captured not long ago by the robots, and had been replaced with one of Meca One's clones. The humans manage to defeat the robots using a sonic amplifier and cause the robots to retreat.
- Exo-Force Online Comics 27-38
- Exo-Force Book 3: Search for the Golden City
- Exo-Force Book 4: Ghost of the Past
- Exo-Force Book 5: Race to the Golden City