The mystery writer, Subaru Mikazuki prefers to stay alone and avoid communicating with others. He lost his father and mother, due to a traffic accident, and it is also exacerbating his life of solitude. One day, he encountered with a stray cat while he is visiting his parents' grave. He decided to bring the cat home to live together because he thought the stray cat gave him inspiration for his work. Subaru was confused about the unfamiliar community life with the cat, but their distance is getting to be close step by step. This beautiful and heart-warming story describes day-to-day life through the eyes of both Subaru(man) and Haru (cat). By accumulating the trivial things of each day, they become "Family".