Ying Xiyan, a girl who has always been very popular in school, doesn't know why she always likes to follow behind the bad boy Qin Kong. One day, she died. Qin Kong was rumored to be her murderer, but Ying Xiyan returned a week later. So her death was just a rumor? But now she doesn't recognize Qin Kong at all... The 'Yan' in 'Ying Xiyan' refers to the swallow in the title, and 'Kong' in 'Qin Kong' to the clear skies in the title.