A young professional named Hinata is walking home when he discovers a kitten in a cardboard box. He decides to adopt the cat, naming him Kyuu-chan, and brings him into his apartment. It soon becomes clear that Kyuu-chan is no ordinary cat, as the feline engages in a range of mischievous yet endearing antics that bring constant surprise and warmth to his owner's previously quiet life. The story is a gentle, slice-of-life comedy that unfolds through a series of four-panel comics chronicling the pair's daily adventures.

The central relationship is between Hinata, a mild-mannered young man, and Kyuu-chan, a playful and curious cat who loves snacks, cuddles, and wearing bow ties. The setting is primarily the cozy, shared home where the two live, though their explorations extend to neighborhood walks and other local spots as they navigate everyday life together. As the series progresses, Kyuu-chan is shown learning ordinary tasks like making popcorn and doing laundry, while Hinata finds himself becoming more active and discovering new joys in simple routines. Notable recurring moments include the heartwarming return of a character known as Ghost-kun, and scenes depicting a full day in Kyuu-chan's life, which consists mostly of naps, small travels, playing with friends, and spending time with Hinata. Through each small chapter, the two companions adapt to life together, learning from each other as they build a unique and loving bond.