"Dawn of the Arcana" is a fantasy romance manga set in a world divided by political strife and racial tensions. The story centers on Princess Nakaba of Senan, a small, impoverished kingdom, who is forced into a political marriage with Prince Caesar of Belquat, a powerful and dominant nation. The marriage is intended to solidify a fragile peace between the two warring countries, but Nakaba and Caesar initially share a strained relationship due to their nations' bitter history and their personal differences.

Nakaba possesses a unique ability known as the Arcana of Time, which allows her to see the past and future of those she touches. This power is tied to the mysterious Arcana, ancient beings revered as gods by some and feared as monsters by others. Nakaba's ability becomes a focal point as the narrative explores themes of destiny, prejudice, and the consequences of power. Her loyal attendant, Loki, a half-human, half-Ajnara (a race with animalistic traits), plays a significant role in her life, offering unwavering support and protection. Loki's Ajnara heritage places him in a marginalized position, highlighting the societal discrimination faced by his kind.

As the story progresses, Nakaba and Caesar's relationship evolves from mutual distrust to a deeper connection, complicated by their conflicting loyalties and the political machinations surrounding them. The narrative delves into the complexities of their marriage, the weight of their responsibilities, and the growing affection they develop despite their circumstances. Meanwhile, tensions between Senan and Belquat escalate, threatening to reignite war. The discovery of Nakaba's Arcana power draws the attention of various factions, including those who seek to exploit her abilities for their own gain.

The manga explores the broader conflict between humans and the Ajnara, as well as the moral ambiguities of power and leadership. Characters are forced to confront their prejudices and question the systems they uphold. Nakaba's journey is one of self-discovery, as she grapples with her identity, her role as a bridge between nations, and the ethical implications of her Arcana power. The story builds toward a climactic resolution that addresses the fate of the warring nations, the true nature of the Arcana, and the personal growth of its central characters.