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.
Haru, un homme de 27 ans, a un QI de 67 dû à son handicap mental, et un comportement émotionnel d'un enfant de 7 ans. Il fait la connaissance de Seo Eun-Hye, une escroc qui ne vit que pour l'argent et ne croit ni en l'amour, ni au destin. Suite à un accident de la circulation, elle se retrouve liée avec Haru à cause d'un mensonge. Eun-Hye rencontre en même temps le docteur Park Dong-Jae, qui a la réputation d'être un génie dans le domaine de la neurologie, et qui cherche à rendre les attardés mentaux intelligents. Il va donner la possibilité à Haru de pouvoir changer sa vie pour toujours, mais à quel prix ?