"NICO/AGONY" is a psychological thriller anime that delves into themes of identity, memory, and the human psyche. The narrative centers on Nico, a young woman who awakens in a desolate, labyrinthine city with no recollection of her past. The city, devoid of life, is filled with cryptic symbols, fragmented memories, and eerie, shifting landscapes that seem to reflect her inner turmoil. As Nico explores this surreal environment, she encounters shadowy figures and distorted versions of people who may or may not be connected to her forgotten life. These encounters often escalate into tense, surreal confrontations, blurring the line between reality and hallucination.

The plot unfolds through a series of nonlinear episodes, each revealing fragments of Nico’s past and the events that led to her current predicament. Flashbacks and dreamlike sequences suggest she was once part of a clandestine research project involving experimental memory manipulation. The project, led by a mysterious organization, sought to erase traumatic memories but inadvertently fractured the identities of its subjects. Nico’s journey becomes a quest to piece together her shattered self, uncovering truths about her role in the experiment and the ethical dilemmas surrounding it.

Key characters include Dr. Agon, a enigmatic scientist who appears in Nico’s visions and seems to hold the key to her lost memories. His motives remain ambiguous, oscillating between a desire to help Nico and a darker, more manipulative agenda. Another significant figure is Rei, a fellow subject of the experiment who shares a fragmented connection with Nico. Rei’s presence alternates between ally and antagonist, reflecting the instability of their shared experiences. The narrative also introduces a recurring entity known as "The Watcher," a spectral figure that observes Nico’s journey, symbolizing her internal struggle with guilt and self-awareness.

The story’s tension builds as Nico uncovers the extent of the experiment’s consequences, not only for herself but for others who underwent the same procedure. The city itself becomes a character, its shifting architecture and oppressive atmosphere mirroring Nico’s psychological state. The climax reveals the true nature of the experiment and Nico’s pivotal role in its downfall, culminating in a resolution that leaves her fate ambiguous, reflecting the series’ exploration of identity and the fragility of memory.