Sixteen years old American girl named Catherine Chiariello moved to Seoul when his dad opened a not-so-big Italian restaurant there. Kim Ryeowook worked in that restaurant as a part-time employee on weekend. He's definitely an older brother whom always dreamt by Cathy, but who knows what will grow up in their sister-brother relationship? Beside, Cathy was trapped in a confusing relationship with her High School's playboy, Cho Kyuhyun...