Jung In Jae, the intern teacher, together with star teacher Kang Se Chan, are the head teachers of Class Two of Grade 2, also known as the class who causes the most trouble. Go Nam Soon was once friends with Park Heung Soo in middle school. However, Nam Soon broke Heung Soo's leg in an accident and has been carrying the guilt ever since. Oh Jung Ho is a troublemaker who bullies his classmates and constantly finds fault with Nam Soon. With both patience and love, Se Chan and In Jae teach and guide the students, in hopes that they will learn and grow under their guidance.