"Noir" is a 26-episode anime series that blends elements of action, mystery, and drama, centering on two female assassins, Mireille Bouquet and Kirika Yuumura, who form a partnership under the enigmatic codename "Noir." Mireille, a skilled and independent assassin from Corsica, receives a mysterious message from Kirika, a young amnesiac girl in Japan who possesses exceptional combat skills but no memory of her past. The message contains a fragment of a melody tied to Mireille's childhood, prompting her to investigate Kirika's connection to her own tragic history.

The two women agree to work together, with Mireille seeking answers about her family's murder and Kirika hoping to recover her lost memories. Their partnership leads them to uncover a vast conspiracy involving a secretive organization known as Les Soldats, an ancient order that has manipulated assassins for centuries. As they carry out contracts and delve deeper into the mystery, they encounter Chloe, another assassin with ties to Les Soldats, who becomes both an ally and a rival.

The narrative unfolds through a series of episodic missions interspersed with overarching plot developments. Each mission reveals fragments of the larger puzzle, gradually exposing the true nature of Les Soldats and its connection to the protagonists. The series explores themes of identity, fate, and the moral ambiguity of their profession, as Mireille and Kirika grapple with their roles as killers and their shared destiny.

The dynamic between Mireille and Kirika evolves throughout the series, shifting from a pragmatic alliance to a deep, almost familial bond. Mireille's pragmatic and calculating nature contrasts with Kirika's innocence and vulnerability, creating a compelling interplay of personalities. The series builds toward a climactic confrontation with Les Soldats, where the protagonists must confront their pasts and the organization's sinister agenda.

"Noir" is characterized by its atmospheric tone, intricate plot, and focus on character development. The story balances episodic action with a slowly unraveling mystery, culminating in a resolution that ties together the personal and thematic threads of the narrative. The series remains a notable entry in the genre, offering a blend of suspense, emotional depth, and philosophical undertones.