Althought Taeyeon and Tiffany is so close, but they don't know the status of their relationship. Couple or just friends ? Tiffany waited for Taeyeon to confess his feelings toward her. But Taeyeon confuse with his feelings and didn't give Tiffany certainly relationship. In silence, Siwon falling in love with Tiffany and he know that Tiffany like Taeyeon.

They just graduated from high school. Taeyeon have to go to America. Taeyeon know that he falling in love with Tiffany when he was at airpot. He want to confess his feeling toward her but something bad happen and make Taeyeon have 3 days to confess his feelings.