Amateur artists often have a great image in their mind, but fail to recreate it outside their heads. It seems professionals aren't safe from this, either - and this manga is one of many such examples.
Imagine a cyberpunk-ish sci-fi world with a complete cultural melting pot, where one of the very few sources of entertainment for the masses are the "dogfights" - staged fights to the death (or destruction) between cyborgs. One of these cyborgs is Sayoko Tachibana, now known as the White Thirteen or Sirius. She sold her body (quite literally) to pay the medical bills for her sick brother Takeru and now, with
her brain as the only human part, she mindlessly bashes cyborg heads in. Takeru isn't having any of this though and breaks his sister out of this enslavement, managing to sorta "awaken" her. Now they're both on the run from the mysterious organization that owns Sayoko's cyborg body and organizes the dogfights, and the big boss Marseille is hell-bent on bringing her back, no matter the cost.
And so the adventure of epic proportions begins. At least in the artist's head; but in reality, the story struggles a lot. A whole LOT. Almost every plot point and side story end up being not what they were hyped up to be. Be it Sayoko herself or any other character, at first there are allusions to greater depths to them, but the story simply doesn't deliver. The overarching plot ends up disappointing as well, as it ultimately does not matter. Nothing matters in the end, yet also somehow resolved off-screen in the epilogue. A-grade storytelling right there. With the appropriate characters to boot. Really, what's up with the villain? What was his deal, his obsession all about? His breakdown in the end is literally out of nowhere. And as said before, it even doesn't matter, he even admits that himself! Also what about Sayoko? All this tension about her living on borrowed time and struggling to preserve her newfound humanity? Doesn't matter, devolves to more cyborg fights. It's also not even about her and her brother, as Takeru has his hands full with his little girlfriend. The silver lining is this minor villain, troop leader Cunningham, who curiously resembles an actual human the most, he is also the one you can really get behind. And even that doesn't matter, he still stays a two-bit villain just because. Did this author ever produce anything coherent?
In the end you'll likely only stay around for the admittedly nice art and the cyborg fights. Those are cool. Everything else is bad and forgettable. Do not read, just skip through and enjoy a nun brutalizing cyborgs.