It is 2047. Five years ago, the earth had been attacked by huge creatures called "mimetic beasts." The countries of the world had united to fight the beasts, and they had managed to fight the creatures back with their giant robots. However, many soldiers died, and a few beasts still survive.
Five years after the epic battle with the mimetic beasts, Goh is close to retired and marrying Anna. But in the middle of the ceremony, Goh is called out to pilot again. Despite Goh's objections, Anna joins the battle.
Goh doesn't want Anna to pilot Neo-Okusaer any more. But Anna doesn't give up, and when a mimetic beast attacks, she tries to fight it with a small school robot. Goh shows up just in time to see her torn clothes among a pile of wreckage.
She still wants to be a pilot though, and this time Goh accepts it.Meanwhile, a beast appears in the South China Sea, and four teams from four different countries respond. Goh shows up with Anna to show her the other teams fighting.
Shizuru, pilot of the Core Gunner once had something of a crush on Goh. But now, she is uncertain if she even belongs at the Dannar Base. A rumor goes around that she's going to quit.
A mimetic beast attacks Cosmo Base in space. The leader of the base stays behind to defend it, and sends his daughter Lou down to earth so she'll be safe. Since she has no family left, Goh and Anna take her in to live with them.
Goh finds out that his old partner Max and girlfriend Mira are alive, but have been in a coma ever since. The scientists run tests on Max and find some strange results. Mira awakes and has not memories of what happened.
Max attacks the base in the Core Gunner. Goh confronts him in Godannar. Max blames Goh for Mira's death. When Shizuru confronts Max, he mutates into some sort of creature.
Repairs are underway at the base. Mira is learning more and more, and there are hints of jealousy in Anna. A mimetic beast attacks. Dragliner deploys with Godannar, but during the fight, all three are shot down.
Rescue teams are sent out to recover the Dragliner, Okusaer, and Godannar. But the mimetic beast is flying around the area, so the rescue has to be delayed.
A mysterious robot fights against a mimetic beast that had been attacking Caucasus 1. He beats the mimetic beast, but causes a huge amount of damage in the process, and refuses to identify himself.
Ken comes to Lou's rescue. Goh and Anna realize he's the one who attacked Caucasus 1, and they confront him. But Lou keeps them from fighting, and Ken gets away. Lou is taken back to base and put in detention.
A mimetic beast attacks Cosmo Base, but neither the Dannar nor the Okusaer are ready to go out, so Shizuru goes out alone in Core Gunner. She fights off the beasts, but is seriously injured and dies.
Two of the base members leaving flowers by Shizuru's death bed make a startling discovery...she's still alive! Reports come in from across the globe of a large number of mimetic beasts, and robots all over the world are trying to fight them.
Recap episode of the first series
Mira has teamed up with Goh in Neo-Okusaer, but he hasn't made any moves toward her because he's waiting for Anna to come back. Kiriko decides it might be time to bring out Go-Okusaer, a prototype of Neo-Okusaer.
Shizuru's test-run with the Go Okusaer fails. On the way back from a battle, Mira faints from shock. Kiriko is worried if they can still use her as a pilot. Anna realizes that she had given up on her dream, and decides to go back to the base.
A female mechanic named Tonko is being pushed into an arranged marriage that she doesn't want. But it turns out that a mimetic beast had stomped on the restaurant where the wedding was to take place, so the arranged marriage is off.
Anna and Shizuru train in order to be able to control the plasma drive. Ekaterina holds a party, but it gets interrupted when more mimetic beasts attack and she has to go out to fight them. Shadow has dreams that she's attracted to Luna.
Kiriko gets Max's data. There have been changes not only to his body, but to his brain as well. Luna gets nervous because it will be her and Shadow's last battle together, and she gets shot down. Shadow thinks Luna's dead and goes berserk.
Moukaku gets into a bar fight, and he's starting to undergo the same mutation as Max and Shadow. He gets it under control though, and later proposes to Shukuyu. Meanwhile, the Commissioners have discovered the cause of the "mutations."
Goh is carrying the virus and is ordered to stop piloting the Dannar.
Ken manages to kill a beast before he mutates completely. But Ken is so pumped up even after the fight that it triggers the virus and he starts mutating. Goh gets into Godannar to stop Ken.
Mimetic beasts are focusing their attacks on the bases. And they've found a way to control the bases' weapons. But just when it seems the beasts have won, they all retreat, heading towards Godannar. Meanwhile, Goh is fighting and beginning to mutate.
Anna's dad, the founder of Dannar Base, resumes control. It turns out that the mimetic beasts have developed the ability to merge together and share their abilities. They've grown into a super-mimetic beast, and the leader has to be destroyed.
Ken and Goh attack the beast, mutating more and more. But the beast is too much for Goh to handle, and it tries to absorb Godannar into itself. Mira attacks Godannar before he can cause too much damage. Anna tries to stop her.
They win against the mimetic beasts, but Goh transforms completely in the process. Years later, Goh and Anna get re-married. During their ceremony, the last mimetic beasts attack. Goh, Anna, and the rest of the pilots go out to fight them.