"My New Life as a Cat" centers around a young man who unexpectedly dies in an accident and is reincarnated as a stray cat. The protagonist, formerly a human, retains his memories and consciousness, allowing him to navigate his new feline existence with a unique perspective. The story explores his adaptation to life as a cat, including the challenges of survival, interactions with other animals, and the complexities of forming bonds with humans.

The narrative delves into the protagonist's efforts to understand his new world, from learning to hunt and avoid danger to grappling with the instincts and limitations of his feline body. His interactions with other cats and animals provide insight into the social dynamics of the animal kingdom, while his encounters with humans highlight the contrast between his past life and his current reality. A key relationship develops with a kind-hearted young woman who takes him in, offering him a chance at a stable life while also reigniting his longing for human connection.

Throughout the series, the protagonist reflects on his past life, his regrets, and the lessons he learns from his new perspective. Themes of redemption, self-discovery, and the value of life are woven into the story as he navigates the duality of his existence—both as a cat and as a being with human memories. The manga balances moments of humor, warmth, and introspection, creating a narrative that is both engaging and thought-provoking.

The main characters include the protagonist, whose internal monologue drives much of the story, and the young woman who becomes his caretaker, offering a human anchor to his experiences. Supporting characters, such as other cats and animals, provide additional layers to the story, enriching the protagonist's journey and the world he inhabits. The series is a blend of slice-of-life storytelling and fantasy elements, offering a fresh take on the reincarnation genre.