"High-Rise Invasion" is a survival thriller anime set in a surreal, dystopian world where characters are trapped in a maze of interconnected skyscrapers. The narrative centers on Yuri Honjo, a high school student who finds herself transported to this mysterious environment after witnessing her brother’s murder. The setting is populated by masked assailants, known as "Masked People," who relentlessly hunt and kill the trapped individuals. These killers are controlled by a mysterious figure referred to as the "Sky King," who orchestrates the deadly game.

Yuri quickly discovers that survival in this world requires both physical and mental resilience. She encounters other survivors, including Rika Honjo, her older brother, who initially appears to be dead but is revealed to be alive and involved in the larger scheme of the world. The survivors are given cryptic instructions through smartphones, which guide them to complete tasks or face dire consequences. The masks worn by the assailants grant them supernatural abilities, making them formidable adversaries.

As Yuri navigates the perilous environment, she forms alliances with other survivors, such as Mayuko Nise, a resourceful and determined girl, and Sniper Mask, a skilled marksman who initially poses a threat but later becomes an ally. The group uncovers fragments of the world’s purpose, learning that it is a constructed reality designed to test human will and morality. The Sky King’s motives remain shrouded in mystery, but it becomes clear that the survivors are pawns in a larger, more sinister game.

The plot delves into themes of trust, survival, and the human capacity for both cruelty and compassion. Yuri’s journey is marked by her struggle to protect her friends while unraveling the truth behind the world’s existence. The series balances intense action sequences with moments of psychological tension, as characters grapple with their fears and the moral dilemmas posed by their circumstances. The narrative builds toward a climactic confrontation with the forces controlling the world, leaving questions about the ultimate fate of the survivors and the true nature of the Sky King’s intentions.