An-chan is a curious three-year-old who lives with her older brother, five-year-old Kantarou. One day, she discovers a strange creature called Oochopus appearing in their home. Together with Kantarou, An-chan welcomes this unpredictable being wholeheartedly into their family, embracing its playfully chaotic antics. Her experiences with Oochopus unfold amidst the familiar backdrop of their daily routines and family life.