"Zombie Zoo" is set in a dystopian world where a mysterious virus has transformed a significant portion of the population into zombies. The story unfolds in a quarantined city where the remaining survivors have established a fortified sanctuary called the "Zombie Zoo." This sanctuary doubles as a research facility where scientists study the infected in an attempt to find a cure. The facility is divided into zones, each housing different types of zombies categorized by their behavior and level of infection.

The protagonist, Akira, is a young researcher who works at the Zombie Zoo. Akira is driven by a personal mission to find a cure, as his younger sister, Yumi, was among the first to be infected. Yumi is kept in a special containment unit, her condition stabilized but not cured. Akira's work is complicated by the arrival of a new strain of the virus, which causes zombies to exhibit unprecedented levels of intelligence and coordination. This development threatens the fragile balance of the sanctuary and raises questions about the nature of the infection.

Akira is joined by a diverse group of characters, including Dr. Haruto, the head scientist who harbors a dark secret about the origins of the virus; Rina, a skilled security officer with a no-nonsense attitude; and Kenta, a former journalist who documents the ongoing crisis. Together, they navigate the ethical dilemmas of their work, the constant threat of zombie outbreaks within the facility, and the growing tension between the survivors and the military forces overseeing the quarantine.

As the story progresses, Akira and his team uncover evidence that the virus may have been engineered, leading to a conspiracy involving powerful corporations and government agencies. The narrative explores themes of survival, morality, and the consequences of scientific experimentation. The series builds toward a climactic confrontation as the team races against time to develop a cure while fending off increasingly intelligent and aggressive zombies. The fate of the Zombie Zoo and its inhabitants hangs in the balance as the true nature of the virus is revealed.