"Galism" is a manga series that explores themes of survival, morality, and the consequences of unchecked scientific ambition. The narrative is set in a dystopian future where humanity faces extinction due to a mysterious plague known as the "Galism Syndrome." This disease transforms infected individuals into grotesque, monstrous beings called "Gals," which exhibit heightened aggression and physical mutations. The world is plunged into chaos as governments collapse, and survivors struggle to maintain order in the face of the spreading infection.

The protagonist, a young man named Shou, becomes central to the story after surviving an encounter with a Gal. Shou discovers he possesses a unique immunity to the syndrome, making him a key figure in the fight against the outbreak. Alongside a group of survivors, including a determined scientist named Dr. Akira and a skilled fighter named Rina, Shou embarks on a journey to uncover the origins of the Galism Syndrome and find a cure. Their mission takes them through ruined cities, abandoned laboratories, and hostile territories, where they face not only the Gals but also other survivors who have resorted to extreme measures to stay alive.

As the group delves deeper into the mystery, they uncover disturbing truths about the syndrome's origins. It is revealed that the Galism Syndrome was the result of a failed bioweapon experiment conducted by a shadowy organization seeking to create superhuman soldiers. The experiment spiraled out of control, leading to the catastrophic outbreak. The survivors must confront the ethical dilemmas posed by the organization's actions while grappling with their own survival instincts.

The series is marked by its exploration of human resilience and the moral ambiguities of scientific progress. Shou's immunity becomes a source of hope for humanity, but it also places him in constant danger as factions vie to exploit his unique condition. The relationships between the characters evolve as they face increasingly dire circumstances, with trust and loyalty tested at every turn. The narrative builds toward a climactic confrontation with the remnants of the organization responsible for the outbreak, culminating in a resolution that leaves the fate of humanity hanging in the balance.