Lu Mei is the younger sister of former EXO member LuHan. During her brother's time in EXO, Mei fell in love with a certain Kim Jongin, whom she dated for two years. Upon her brother's departure from the group, and the siblings leaving Korea and returning to their home country, China, Mei had no choice to break it off with Jongin, even though it wasn't what either of them wanted. Flash forward a year. Mei has found a new relationship with a boy named Zhao Tengfei. Though she can't particularly say she's happy. After all, she left her heart with Jongin a year ago, and he's the only one who holds the key. What happens when after a year without seeing each other, Mei and Jongin finally meet face to face again when Luhan invites the EXO boys to China for a visit? Relationships are rekindled, feelings are resurfaced, and Mei is left lost and confused. What's a girl to do when she's left her heart with someone who won't give it back? And what makes it worse? An unexpected contender makes an attempt to steal Mei's heart. And unbeknownst to Mei's conscious feelings, she doesn't mind giving it to him.