Doc Ido, a doctor and mechanic who lives and works in the hellish, postapocalyptic Scrapyard, finds the—miraculously preserved—remains of a female cyborg in a junk heap. After he revives and rebuilds her, the preternaturally strong, amnesiac Gally begins to forge a life for herself in a world where every day can bring a fight for life. The 1993 Gunnm anime adapts the first two volumes of the Gunnm manga.

In the heart of Italy, the Social Welfare Agency rescues young girls from hospital beds and gives them a second chance at life using the latest in cybernetic advancements. With their artificially enhanced bodies, the girls are brainwashed and trained as assassins to carry out the dirty work of the Italian Government. Despite all the modifications, they are still just children at heart, struggling for recognition from those they love, even knowing the love they feel is manufactured. This tragic tale unfolds as these girls grapple with their emotions in an agency that treats them as nothing but ruthless killers.

Owing to an increasing debt, Kaiji Itou ends up resuming his old lifestyle. One day, while walking on the street, he stumbles upon Yuuji Endou, who is hunting Kaiji due to the money he owes to the Teiai Group. Unaware of this, Kaiji eagerly follows Endou, hoping for a chance to participate in another gamble, but soon finds out the loan shark's real intentions when he is kidnapped. Given that Kaiji is unable to pay off his huge debt, the Teiai Group instead sends him to work in an underground labor camp. He is told that he will have to live in this hell for 15 years, alongside other debtors, until he can earn his freedom. His only hope to put an early end to this nightmare is by saving enough money to be able to go back to the surface for a single day. Once he is there, he plans to obtain the remaining money needed to settle his account by making a high-stakes wager. However, as many temptations threaten his scarce income, Kaiji may have to resort to gambling sooner than he had expected.

After one of his coworkers fails to repay a debt, apathetic bum Kaiji Itou is pressured by loan sharks to settle the large sum of cash. Since Kaiji has little money and no future prospects of his own, he is unable to return what his colleague borrowed. Faced with massive financial burdens, Kaiji is given an offer to board the illustrious Espoir—it is said that one night aboard the ship, and all of your debts will be paid. What seems like a simple night of gambling quickly turns into a game of strategy and betrayal. With the losers of the tournament being subjected to a backbreaking life of indebted servitude, Kaiji must choose his actions—and allies—carefully. However, this is only the beginning of a series of gambles that will wager Kaiji's life, testing the full extent of his wits and will to survive.