Nana and Shota are a newlywed couple and Nana is 15 years older than Shota. Nana works as a designer and Shota works as a gym trainer. They both enjoy mystery. The newlywed couple then move to an apartment and they attend a resident’s meeting there. Nana and Shota become involved in murder cases that take place at the apartment. Residents get murdered one by one. Some residents have a motive, but those suspects have an alibi. Because of this, an arrest has yet to be made.

Lü Guichen is the heir of the nomadic Qingyang tribe, and is sent to the Eastern Land as hostage. He meets Ji Ye, an unfavoured illegitimate son who is training to become a warrior, and Yu Ran, the princess of the Winged tribe. The three become close friends, and the boys’ feelings for Yu Ran soon turn romantic. At the same time, powerful warlord Ying Wuyi has been maintaining a firm control over the Emperor, giving him unprecedented power over the nobles. Lü Guichen, Ji Ye and Yu Ran decide to join the decisive battle against Ying Wuyi at Shangyang Pass, but unbeknownst to them, an even darker conspiracy is yet to unfold.