A Shim Hyung-rae comedy children's film where he disguises himself as a spirited, energetic grandmother. At Grandma Ttosun's boarding house, her daughter Taesun, security guard Mr. Jo, a graduate student, an office worker, and an aerobics instructor live together. Grandma Ttosun, a former policewoman, trains physically every day, making her agile and incredibly strong. One day, Mr. Jo witnesses a drug deal and is chased and killed by criminals. The grandmother learns that the police chief is involved in the case and decides to expose the truth. However, all the boarding house residents are captured while trying to help catch the villains, leaving Grandma Ttosun to confront them alone. With her superior intelligence and martial arts skills, the grandmother defeats the villains and rescues the boarding house residents safely.