Haru is a mentally challenged young man with an IQ of 65 points and the emotional age of a seven-year-old. He misses his mom, who abandoned him at a bus stop after buying him a strawberry ice cream, and dreams of becoming a bus driver so that he can go meet with his mom someday. One day, he falls in love with the swindler Eun-hye, who disguises herself as a teacher of mentally retarded students to avoid the police. To win her heart, Haru undergoes a high-risk surgery conducted by psychosurgeon Dong-jae. The surgery ends successfully, and Haru is reborn into a genius with an IQ of 180 points. He also becomes rich and famous, but turns out that it is not enough to make him happy.