"A.I.C.O. Incarnation" is a science fiction manga series set in a near-future Japan, where a catastrophic event known as the "Burst" has devastated the region of Kurobe Gorge. The Burst was caused by an out-of-control artificial life form called "Matter," which consumes and replicates organic material, spreading uncontrollably. The government establishes a quarantine zone around the affected area, isolating the region to prevent further contamination.

The protagonist, Aiko Tachibana, is a high school student who lost her family in the Burst and now lives with her friend Yuya Kanzaki. Aiko suffers from amnesia and relies on Yuya for support. However, her life takes a dramatic turn when a mysterious transfer student, Kazuki Minase, reveals that Aiko is not entirely human. She is a synthetic being created to house the consciousness of the original Aiko, who was critically injured during the Burst. The real Aiko's body is being held captive within the quarantine zone, and her consciousness must be reunited with it to prevent the Matter from evolving further.

Kazuki recruits Aiko and Yuya to join a team of specialists tasked with infiltrating the quarantine zone. The team includes members with unique skills and cybernetic enhancements, such as Haruka Seri, a skilled sniper, and Isao Inaba, a former soldier. Together, they embark on a dangerous mission to reach the heart of the Burst, where the original Aiko's body is located. Along the way, they face numerous challenges, including hostile Matter creatures, government interference, and internal conflicts within the team.

As the story progresses, Aiko learns more about her origins and the true nature of the Burst. The Matter is revealed to be a product of advanced biotechnology gone awry, and its evolution poses a significant threat to humanity. Aiko's dual existence as both a synthetic being and the carrier of the original Aiko's consciousness becomes central to the narrative, raising questions about identity, humanity, and the ethics of scientific experimentation.

The series explores themes of sacrifice, resilience, and the consequences of unchecked technological advancement. Aiko's journey is one of self-discovery and determination, as she grapples with her identity and the responsibility of stopping the Burst. The supporting characters each contribute to the story's depth, with their own motivations and struggles adding layers to the overarching plot. The manga balances action, mystery, and emotional depth, creating a compelling narrative that keeps readers engaged until its resolution.