i know, the description was kinda boring but, please belive me, the story is better than the description.

Sulli is an ordinary girl. Her sister, Tiffany had the disease thalassemia. Her parents fight every day because a simple thing. So, when sulli was 17 years old, she move to korea. At korea she meet her childhood, Taemin.

Sulli never know that Taemin like her , because taemin never tell every one about it. At the school sulli and taemin being a classmate. Sulli being friend with Amber, Victoria, Luna, Krystal

 When Sulli and taemin was already being a girlfriend-boyfriend, Sulli’s sister Tiffany come to korea and change everything.

At the last sulli have to choose her life or her sister's life.