While Gunbuster's final mission destroyed the space monsters' star system, the intergalactic war still continues. Earth's only hope lies in the hands of "TOPLESS", an elite mecha group with children possessing supernatural powers and new Buster Machines. Among their ranks is a rookie named Nono and the ace pilot Lal'C - whom Nono looks at as a "big sister". Together with their teammates Nicholas and Chiko they must aim for the top and protect all of mankind from the wrath of the space monsters. 
(Source: Anime News Network)

In the very near future, a race of huge, insect like aliens is discovered traveling the galaxy. These aliens seem dedicated to the eradication of the human species as it takes its first steps away from the solar system, and they are getting closer and closer to Earth. Humanity has responded by developing spacegoing battleships and giant fighting robots. These robots are piloted by the best and brightest of Earth's youth, picked from training schools around the world. 
The story begins in the year 2023, not long after the first battles with the aliens, and centers on young Noriko Takaya. Although Noriko's father was a famous Captain in the space fleet who was killed during one of the first battles of the war, her own talents as a pilot are questionable. Nonetheless, she has entered a training school. Through the series Noriko, joined by the beautiful and talented Kazumi Amano, will fight to overcome the trauma of war, the doubts of her peers, and her own lack of confidence. 
(Source: AniDB)

This double feature comprises of Gunbuster and Die Buster (aka Gunbuster 2) condensed them into a single theatrical release told in two parts with a musical intermission in between. The first part, Gunbuster the Movie, condenses the six episodes of the original OVA into a 95-minute moviefeaturing a new 5.1 audio remix and a redub by the original Japanese cast. The second part, Die Buster the Movie, mixes large chunks of the second OVA series with a few altered or newly-animated scenes to create a truncated take on Nono's story. 
(Source: Anime News Network)

Similar to the Gunbuster! Science Lesson these are short "omake" bonus features bundled on the Blu-ray Box Complete Edition of the Top wo Nerae 2! Diebuster.

Each short lasts around three minutes, and features super deformed versions of Nono, Lal`C Melk Mark and the Dix-Neuf explaining the various scientific aspects of the series.


Top wo Nerae 2! follows the story of Nono, a country girl who dreams of becoming a space pilot (or to be more precise, 'like Nonoriri,' the meaning of which is revealed as the series progresses) who, due to a chance encounter with an actual space pilot finds herself becoming part of the elite Fraternity. Made up of teenage pilots called Topless, and armed with quasi-humanoid weapons called Buster Machines, the Fraternity's mission is to protect the people of the Solar System from attack by swarms of uchuu kaijuu (literally, space monsters). 
Chapter 1, the only proper chapter, tells the story of Nono's first meeting with Lal'C - the aforementioned space pilot and a girl that Nono instantly adores, dubbing her oneesama (big sister).

The [graphic] novel mentions the world between 2050-2500, before Gunbuster have yet come back to Earth, and some plot actually consistent with Top 2 Diebuster. 
(Source: Wikipedia)

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