Lal’C is welcomed to the Imperial City of Lunar Tokyo by the governor, who apologizes for not organizing a welcome parade. He explains that like Earth, the Moon has been evacuated. He says it’s time for Earth rise, but the ultra large scale ether-accelerated assault weapon Douze-Mille is in the way. Lal’C thinks back to a time when Nono talked about going to Earth before she is spot checked. Niigo speaks to the elders of the Privy Staff Council and explains that over the past six months the Buster Corps surrounding the solar system have vanished. He adds that the body they had been gathering to form had recently vanished as well. The elders ponder about Nono, but Lal’C enters and says to forget about her. The elders ask if mankind must go so far to survive, and Lal’C says that sacrificing the Earth is their only hope. They entrust the key to Douze-Mille to Lal’C and she leaves afterwards. The elders lament that humanity can still only cower in fear and they view an image of the recently uncovered Eltreum. Hatori and Nicola watch the Buster Machines gather and Hatori asks if Nicola feels betrayed by them. Nicola says that Topless are just batteries to be used up and tossed away. Casio chats with Tycho, who tells her he tried to meet with Lal’C but got a black eye for his troubles. Tycho says that’s to be expected since there was an assassination attempt on Mars and not even Tycho could meet her after that. Lal’C recalls taking a photo with Nono, so she gathers all the Topless and has them take a picture together. Tycho gives her a message from Casio but also notices that Lal’C has a fever. Two months earlier, Lal’C had visited the man who had found Nono and he recognized her right away. They chat, and he says that Nono liked Japanese food because Nono-Riri was a traditional Japanese girl. Lal’C says apparently Nono-Riri was someone who had saved the Sol System in the past and the man wonders if it was the same for Nono. He wonders what part of the Sol System Nono was created to protect and why she was given human form. He says if Nono-Riri really was a normal girl, then she would need a friend and that Nono was probably happy to have met Lal’C.
The Exelio Fluctuating Gravity Well’s warp out is detected, and Niigo explains to fleet commander Zaha Hadid that the plan is to knock the Gravity Well into the black hole using Douze-Mille. Hadid says they’ll buy time for Lal’C and laments how the Topless are barely older than her own daughter. Exotic Maneuvers lose effectiveness near the Gravity Well, so Tycho tells everyone to stay as a group. Gravity Well grunts appear and the Topless engage them before the Exelio Gravity Well, now in its larger third evolution form, appears. Lal’C prepares Douze-Mille for activation and Hadid tells her to bring it, and the pilot, back in one piece. Lal’C removes her seal and Dix-Neuf starts up Douze-Mille which has converted Earth into humanity’s ultimate weapon. Douze-Mille launches, moving Earth on a collision course with the Exelio Gravity Well. Niigo says their victory is assured but Hadid hopes Lal’C feels the same way. Lal’C activates the Exotic Drive and Earth accelerates to sub-light speed. In transit, a giant machine resembling Nono warps out. Identifying itself as Diebuster, it proceeds to try and stop Douze-Mille. Lal’C turns part of Douze-Mille into a giant Buster Machine and attacks Diebuster. She tells Nono that humanity’s battle has nothing to do with her, and admits that if Nono had stayed her friend, Lal’C wouldn’t have been afraid of losing her Topless power. She says she wanted to be called Lal’C rather than big sister but before she can hit Diebuster again, Douze-Mille breaks apart. Lal’C notes that she can’t hear Dix-Neuf’s voice anymore and Tycho realizes Lal’C has lost her powers. The Earth stops moving and Diebuster attacks the Exelio Gravity Well with an Ultra Lightning Kick and then follows up with a Buster Collider attack, but it doesn’t work. Diebuster then fires a Buster Beam point blank, but the energy wraps around the black hole and is fired back at Diebuster instead, making her crash into the Moon. The Gravity Well fires on the Earth, but Diebuster sacrifices both arms to block it. Diebuster continues taking damage while Lal’C remembers Nono saying that Nono-Riri was just a normal girl. She hears Nono say her name, so she heads into Dix-Neuf’s emergency spinal passage. A shockwave makes her lose a tooth, but Lal’C continues on until she gets to the horn in Dix-Neuf’s eye. Dix-Neuf pulls the horn out himself, unlocking the true cockpit located in his brain. Lal’C enters the cockpit as Diebuster is damaged further. Lal’C changes into the Top Squadron uniform that was in the cockpit and has Dix-Neuf tear open his chest. He takes a degeneracy reactor from one of the Buster Corp machines and puts it inside his chest, allowing him to assume his true form as Buster Machine #19. Lal’C asks Nono what she’s doing and tells her that power isn’t based on the size of the body, but the strength of the heart. She says it’s about hard work and guts, and Nono flies out of Diebuster’s remains. Together they perform the Lightning Double Kick and destroy the Exelio Fluctuating Gravity Well. At the same time, they crack the black hole which threatens to cause a second Big Bang. The remains of the Buster Corps form giant hands and contain the black hole. In the Polydimensional Space, Space-Time Censor Room, Nono tells Lal’C what she imagines visiting Lal’C’s house would be like before saying that Nono is going to take the singularity and give Lal’C her singularity in exchange. The giant hands collapse in on themselves and explode harmlessly. Lal’C wakes up in Casio’s arms and opens her hand to find an origami crane.
Ten years later on Earth, Lal’C is working as an environmentalist. She talks on the phone with Tycho who is on Pluto and about to leave to protect a diplomatic envoy to the Sirius star system. Tycho asks about some festivals and notes that they’re too old to believe in wishes, but Lal’C tells her that an observatory has conformed something. Lal’C makes her way to the top of a hill and watches as all the city lights shut off. She looks to the stars and sees a moving light, saying that Nono-Riri is coming back. That night, Buster Machines #1 and #2 along with their pilots returned home.
Humans are quite expedient, aren’t they? First Topless are heroes, then they’re diseased, and now they’re heroes again. Let it be known that I think throwing the Earth at something is the stupidest idea ever but that’s what they came up with to stop the Exelio Gravity Well. Diebuster makes its appearance and puts a stop to that plan, but she’s powerless against the Gravity Well herself. Thankfully Lal’C awakens the power of hard work and guts and the threat is defeated! If it’s shout outs to Gunbuster, this episode is chalk full of them! The Eltreum appears, Diebuster is designed after the Top Squadron uniform, Lal’C finds the uniform in Dix-Neuf’s cockpit and even proceeds to tear it off in the same manner Noriko did in Gunbuster’s last episode. This was a great finale, pulling out the epicness one would expect from this series. From the Earth sized Diebuster’s entrance to Nono’s sacrifice, it really gets the heart juices flowing! The epilogue especially is great when you realize exactly what is going on. Yes, Nono-Riri was Noriko all along, and Diebuster’s ending is 12,000 years after the events of Gunbuster. Seeing that WELCOME BACK once more makes the tears threaten to spill out again. So is Diebuster as great as Gunbuster? No, it’s not. Is Diebuster a good show in its own right? Definitely! It is still a worthy sequel and something I definitely recommend checking out. You won’t regret it.