Can a young woman prove her loyalty to her country and her family? Lan Yan Zhi is a privileged banker’s daughter in Shanghai and a student activist who mistakenly comes into possession of a letter from the Japanese Army in 1937. She gets misunderstood for a spy by her crush, Zhou Yu Hao, an upstanding officer in the Chinese Army. To prove her innocence, Yan Zhi agrees to infiltrate the home of her best friend, Feng Man Na, and help Yu Hao track down a mysterious “Mister Traitor.” But what will Yan Zhi do when the search leads to a member of her own family?