Yun-ho Lee (played by Il-woo Jeong) is good at high-kicking martial arts, crazy about motorcycles, and hates studying. Min-ho Lee (played by Hye-sung Kim) is a top student who enjoys making friends online. They are brothers with a one-year age difference and classmates in the first year of high school. These two characters humorously represent two very different archetypes of Korean teenagers. Of course, these two also have their families. Their father, Joon-ho Lee (played by Joon-ho Jeong), became a professional stock trader after retiring early and is an optimistic man. Their mother (played by Hae-mi Park) is a confident Korean medicine doctor. Their grandfather, Soon-jae Lee (played by Soon-jae Lee) is someone who loves money more than anything else in this world. And their grandmother (played by Moon-gye Roh) is someone who always ends up losing in battles with her daughter-in-law.