"World, Before You End" is a science fiction anime series set in a near-future world where humanity faces an impending apocalypse caused by a mysterious phenomenon known as the "Collapse." The Collapse manifests as a series of catastrophic events, including natural disasters, technological failures, and the sudden appearance of anomalies that defy scientific explanation. The story centers on a group of individuals brought together by fate, each possessing unique abilities tied to the Collapse, as they attempt to uncover its origins and prevent the end of the world.

The protagonist, Kaito Arisawa, is a former physicist who lost his family in an early Collapse event. Haunted by guilt and driven by a desire for redemption, Kaito joins a clandestine organization called the "Chrono Vanguard," which investigates the Collapse and its anomalies. The organization is led by Dr. Aya Shimizu, a brilliant but enigmatic scientist who believes the Collapse is not a random occurrence but a deliberate act tied to humanity's misuse of advanced technology. Kaito's journey intertwines with that of Rin Saito, a young woman who possesses the ability to manipulate time in localized bursts, a power that becomes crucial in their fight against the Collapse.

As the series progresses, the group uncovers fragments of a larger conspiracy involving a shadowy entity known as "Eidolon," which appears to be orchestrating the Collapse from an alternate dimension. The team encounters other individuals with unique abilities, such as Haruto Miyake, who can communicate with the anomalies, and Yuna Takahashi, whose visions of the future provide cryptic clues about the Collapse's progression. Together, they navigate a world unraveling at the seams, facing moral dilemmas, personal sacrifices, and the ever-present threat of annihilation.

The narrative is structured around a series of episodic missions, each revealing more about the Collapse and the characters' interconnected pasts. Themes of time, causality, and the consequences of human ambition are explored as the group races against time to decipher the Collapse's true nature. The series culminates in a climactic confrontation with Eidolon, where the characters must confront their deepest fears and make irreversible choices to save what remains of their world. The ending leaves room for interpretation, with the fate of humanity hanging in the balance as the Collapse reaches its final stages.