Subaru Natsuki, an ordinary teenager, is suddenly transported to a fantasy world while returning home from a convenience store. Upon arrival, he discovers he has no special abilities or powers, unlike typical protagonists in similar settings. Shortly after, he encounters Emilia, a half-elf girl searching for a stolen insignia, and her spirit companion, Puck. Subaru decides to assist her, forming a bond that becomes central to the narrative. However, Subaru soon realizes he possesses a unique ability called "Return by Death," which allows him to return to a specific point in time upon dying. This power comes with significant emotional and psychological tolls, as he retains the memories of each death and must relive traumatic events to alter outcomes.

The story unfolds in a world filled with political intrigue, magical beings, and complex relationships. Subaru becomes entangled in the royal selection, a contest to determine the next ruler of the Kingdom of Lugnica, in which Emilia is a candidate. Other candidates include Priscilla Barielle, a haughty noblewoman; Crusch Karsten, a skilled warrior; Anastasia Hoshin, a shrewd merchant; and Felt, a street thief with a mysterious background. Each candidate has their own motivations and supporters, adding layers of conflict and alliances.

Subaru’s journey is marked by his efforts to protect Emilia and those he cares about, often relying on his ability to reset time to prevent tragedies. However, his repeated deaths and the burden of his knowledge strain his mental state, leading to moments of vulnerability and despair. Key supporting characters include Rem and Ram, twin maids serving Roswaal L. Mathers, a powerful mage and Emilia’s benefactor; Beatrice, a centuries-old spirit residing in Roswaal’s mansion; and Reinhard van Astrea, a knight renowned for his strength and nobility.

The narrative explores themes of perseverance, sacrifice, and the consequences of one’s choices. Subaru’s growth is central to the story, as he learns to navigate the challenges of his new world while grappling with the moral and emotional weight of his power. The series balances intense action sequences with moments of introspection, creating a compelling blend of fantasy, drama, and psychological depth. The intricate world-building and character dynamics contribute to a rich and engaging storyline that keeps viewers invested in Subaru’s journey and the fate of those around him.