In-gyu is 30 years old, but his intelligence level is like that of a 10-year-old. His mother, Ae-chun, takes care of him every day. Although life is a bit hard, the two of them often live a life full of laughter. Until Ae-chun was diagnosed with terminal cancer, she knew that she could not take care of this big child for the rest of her life. She decided to prepare for her son. On this farewell journey of laughter and tears, In-gyu has to learn how to fold his own quilt, cook, take the bus, find a job... He must learn to grow up and say goodbye to his mother.