Won Seo-Jun, Song Yun-Seo and Hwang Eun-Seo are best friends since there childhood, Last summer when they went to beach they had an accident near water and Hwang Eun-Seo died, No one know whether it is an accident or a murder but Song Yun-Seo thinks Won Seo-Jun is the one who killed her sister. Can they find what happened to Hwang Eun-Seo, Can Love bloom between Seo-Jun and Yun-Seo.