"Kaiba" is a 12-episode anime series set in a futuristic world where memories can be stored, transferred, and traded as commodities. The story begins with a young man named Kaiba, who awakens in a decaying room with no memory of his past. The only clue to his identity is a locket containing a photo of an unknown woman. The world he inhabits is one where bodies are interchangeable, and memories can be bought and sold, creating a stark divide between the wealthy, who can afford immortality, and the poor, who are forced to sell their memories to survive.

Kaiba embarks on a journey across various planets and space stations to uncover his lost memories and understand his connection to the woman in the locket. Along the way, he encounters a diverse cast of characters, including Neiro, a rebellious girl with a strong sense of justice, and Popo, a carefree yet enigmatic figure. These characters often serve as mirrors to the societal issues explored in the series, such as class disparity, identity, and the ethical implications of memory manipulation.

As Kaiba travels, he discovers fragments of his past, including his role in a revolutionary movement against the oppressive system that controls memory trade. The narrative delves into themes of love, loss, and the essence of humanity, often blurring the lines between reality and memory. The series also explores the consequences of a society where memories can be altered or erased, raising questions about the nature of self and the value of personal history.

The plot is nonlinear, with episodes often focusing on self-contained stories that contribute to the overarching narrative. Each episode introduces new characters and settings, many of which reflect the broader societal issues at play. The series culminates in a revelation about Kaiba's true identity and his connection to the woman in the locket, tying together the fragmented narrative threads and providing a resolution to his quest for self-discovery.

"Kaiba" is notable for its unique art style, which contrasts with its dark and complex themes, but the focus here remains on the narrative and its exploration of memory, identity, and societal structures. The series presents a thought-provoking examination of a world where the boundaries of self are fluid, and the consequences of such a reality are both personal and universal.