Miyu is an eighth-grade girl whose parents have been hired by NASA. They depart for America, leaving Miyu in the care of Mr. Saionji. Later, Mr. Saionji decides to embark on a one-year trip to India, leaving Miyu alone with his son, Kanata. Complications arise when an alien baby and his babysitter pet crash-land in their house. To make matters worse, the alien baby begins calling Miyu and Kanata Mom and Dad, while also displaying ESP powers and floating around.