Jiyong, Chaerin and Sandara are childhood friends. Jiyong was in love with Lee Chaerin without notice that the quiet Sandara have feelings for him. When Jiyong have to move to London because of his father, he promise Chaerin that he will still contact her through email. Chaerin disagree and never reply any of Jiyong email but instead Sandara reply him through Chaerin name. Fifteen years pass their relationship bloomed, Jiyong thought he knew Chaerin more when it was Sandara. His parents went back to Seoul for 2 weeks and from there he knew the truth. So now is up to Sandara and Jiyong to make everyone believe that he mistook his love for different people and they have to accept him and Sandara love.