"What He Who Doesn't Believe in Fate Says" is a manga series that explores themes of destiny, human connection, and personal agency through its intricate narrative and character dynamics. The story centers on Haruto, a young man who firmly rejects the concept of fate, believing that life is shaped solely by individual choices and actions. His worldview is challenged when he encounters Sora, a mysterious girl who claims to have the ability to see the threads of fate that bind people together. Sora’s presence introduces Haruto to a hidden world where fate is not only real but actively manipulated by individuals known as "Weavers," who possess the power to alter the destinies of others.

As Haruto becomes entangled in this world, he discovers that his own fate is intertwined with a larger, more dangerous conflict. The Weavers are divided into factions, each with differing philosophies on how fate should be governed. Some seek to control destiny for personal gain, while others aim to preserve the natural order. Haruto’s skepticism and determination to forge his own path make him a wildcard in this struggle, drawing the attention of both allies and adversaries. Sora, who initially appears as an enigmatic guide, gradually reveals her own complex motivations and connection to the Weavers, adding layers of intrigue to their relationship.

The narrative delves into the moral and philosophical implications of manipulating fate, questioning whether free will can truly exist in a world where destiny can be rewritten. Haruto’s journey is marked by his internal conflict as he grapples with the possibility that his choices may not be entirely his own. Supporting characters, including other Weavers and individuals whose fates have been altered, provide additional perspectives on the central themes, enriching the story’s exploration of agency and interconnectedness. The plot unfolds through a series of escalating confrontations, revelations, and personal growth, culminating in a climactic resolution that challenges the characters’ beliefs and reshapes their understanding of fate and free will.