Shin Se Kyung and Shin Shin Ae (Seo Shin Ae) are a pair of sisters who came to work as maids in Foodstuff company President Lee Sun Jae's house after their debt-ridden father Shin Dal Ho (Jung Seok Yong) runs away leaving them to fend for themselves. Due to the sisters living their lives in the mountains, everything in the city (outside world) are both new and curious for them especially for the younger sister, Shin Ae. Living together with President Lee is his daughter Lee Hyun Kyung, son-in-law Jung Bo Suk, doctor-to-be son Lee Ji Hun, grandson Jung Jun Hyuk who is a high school student and grand-daughter Jung Hae Ri' Jun Hyuk's school deen, Kim Ja Ok, is in love with President Lee who is widowed.
Lee Yoon Ho, a motorcycle mania who engages in many fights at school and is known for his high kick, and Lee Min Ho, who enjoys spending time on scale models and web blogs, are brothers born a year apart but attending the same class at school. These two portray completely opposite Korean teenage characters in a comical way. And of course, there's the rest of the family. Their father, a full-time stock investor since being laid-off from work, nevertheless optimistic and reckless; their mother, an oriental medicine doctor and always overly confident; their grandfather, who loves money more than anything in the world; their grandmother, who is always defeated by her daughter-in-law in ongoing status quarrels, are some of them. Their uncle Lee Min Yong is a 27-year-old single dad. After going through a premature marriage and early divorce, he enjoys his life back in the dating scene with his half-single and half-married status, while continuing to encounter emotionally-involved moments with his ex-wife Shin Ji at times. Smooth High Kick! is a situation comedy, which portrays the everyday lives of the main characters colliding with each other in a comical way. However, at a certain point, the surprising mysteries of their seemingly-normal surrounding characters begin to unravel one by one.