Joo-Bong’s (Jung Yoon-Suk) father Sang-Goo (Kim Jung-Tae) struggles to attain copyright over the animation character Bongbong. Meanwhile, Joo-Bong's mother left their family, but Joo-Bong believes in his mother's promise. She told him that she would return before he becomes a middle school student, but Joo-Bong decides to go to Japan to meet his mom.