A young man named Renta Neji, an eighteen-year-old ronin student, loses his life after a heroic act. While taking a break from studying, he dives into a river to rescue a drowning kitten, an act that triggers his severe cat allergies, causing him to fall down the stairs and die. The kitten he saved is no ordinary stray; it is Mii-chan, a beloved divine pet belonging to a goddess. In gratitude for saving her cherished companion, the goddess offers Neji a second chance. He chooses to be reincarnated in a fantasy world, hoping for a peaceful new beginning. However, the fiercely attached Mii-chan follows him into this new realm, and the goddess, in a moment of panic, bestows upon him an unusual power: the skill to summon high-quality cat food and cat supplies. Now renamed Nero, he sets out in the Kingdom of Lumiel with his divine feline companion, aiming for a slow, fluffy life, only to find that his unique abilities lead to unexpected adventures.

The central relationship is between Nero and Mii-chan. Despite his former allergy, Nero becomes devoted to caring for the cat, who remains a kitten forever. Mii-chan is not just cute but also a powerful divine being whose presence often influences their journey. While Nero had hoped for a quiet existence, his skills as a cat supplies summoner prove more versatile than expected. His ability to conjure items like cat food and other goods helps him in various professions, from working at the guild using his appraisal skills and cooking prowess to becoming a merchant and exploring dungeons. The narrative focuses on their daily life in this other world, emphasizing heartwarming interactions with the local populace and the gathering of other fluffy companions.

The story follows a largely episodic format as Nero and Mii-chan navigate their new reality. Key narrative arcs include Nero's initial struggle to understand his cat supply summoning skill and find a way to support himself and Mii-chan. Another significant development is the gradual expansion of their family, as other creatures, such as a Cait Sith, are drawn to them, adding to the fluffy atmosphere of their slow-life adventure. Unlike many isekai protagonists who gain overwhelming offensive power, Nero must rely on his wits, his culinary talents, and the practical applications of his seemingly mundane skill to overcome challenges, all while being accompanied by his adorable and sometimes troublesome divine cat.