"Shattered Angels" is a 12-episode anime series that blends elements of science fiction, romance, and fantasy. The story is set in a world where a mysterious phenomenon known as the "Absolute Angels" has caused widespread destruction. These Angels are powerful beings who possess immense strength and are bound to specific individuals called "Contractors." The narrative centers on Kuu Shiratori, a high school student who lives a seemingly ordinary life until he encounters a girl named Setsuna, who claims to be his Absolute Angel. Setsuna is one of several Angels who have emerged in the world, each tied to a Contractor and capable of wielding extraordinary abilities.

As Kuu becomes entangled in the world of Absolute Angels, he learns that these beings are not merely tools of destruction but are also tied to a deeper, more complex system. The Angels and their Contractors are part of a larger conflict involving a secretive organization known as the "Crimson Realm," which seeks to control the Angels for its own purposes. Kuu’s relationship with Setsuna evolves as they navigate the challenges posed by this organization and other rival Contractors, each with their own motivations and agendas. The series explores themes of loyalty, identity, and the consequences of wielding power, as Kuu and Setsuna struggle to understand their bond and the true nature of the Angels.

The supporting cast includes other Contractors and their Angels, such as Koyori, a cheerful yet enigmatic girl who becomes a key ally, and Takuto, a rival Contractor with a tragic past. The interactions between these characters drive much of the narrative, as alliances shift and secrets about the Angels’ origins are gradually revealed. The series balances action-packed sequences with moments of introspection, delving into the emotional and psychological toll of being a Contractor. As the story progresses, Kuu and Setsuna must confront the ultimate truth about the Angels and their purpose, leading to a climactic resolution that ties together the series’ central conflicts.