"Sexy Voice and Robo" is a manga series written and illustrated by Iou Kuroda, serialized between 2000 and 2002. The story centers on Nico Hayashi, a 14-year-old girl with a knack for mimicry and a sharp intuition, who becomes involved in solving mysteries and uncovering secrets in her urban environment. Nico operates under the alias "Sexy Voice," using her ability to impersonate voices and her natural curiosity to navigate the underbelly of Tokyo. She often collaborates with Kuroi Robo, a 29-year-old otaku and model kit enthusiast, who provides technical support and serves as her reluctant partner in these adventures.

The narrative unfolds through episodic cases, each exploring different facets of Tokyo's hidden layers, from petty scams to more serious criminal activities. Nico's youthful perspective and resourcefulness drive the investigations, while Robo's grounded, often skeptical demeanor balances her impulsive nature. Their dynamic is central to the series, blending humor and tension as they tackle cases that range from the mundane to the bizarre.

Themes of identity, communication, and the intersection of technology and human interaction are woven into the story. Nico's ability to manipulate voices symbolizes the fluidity of identity in a modern, interconnected world, while Robo's obsession with model kits reflects a longing for control and precision in an unpredictable reality. The series also delves into the lives of secondary characters, offering glimpses into their struggles and motivations, which often intersect with Nico and Robo's investigations.

"Sexy Voice and Robo" is notable for its grounded portrayal of urban life, blending slice-of-life elements with mystery and intrigue. The manga's pacing and structure allow for both self-contained stories and overarching character development, creating a cohesive narrative that explores the complexities of human relationships and the hidden stories within a bustling metropolis.