Plum, as her family calls her, is a tiger-striped cat that lives with Miss Nakari, a single mother to her teenage son, Taku. Plum can understand what people say to her, and she can even tell what's in their minds. She also has many friends among the neighbourhood cats. All is well in her everyday life, until the day a mischievous kitten named Snowball joins Plum's happy household. Will the naughty little newcomer turn Plum's world completely topsy-turvy? Or will Snowball make her life even sweeter?