In the prosperous age of Chang'an, a copper coin engraved with "eyes" at the Shangyuan Lantern Festival led to a shocking mystery. Yang Guizhong, a capable prison officer, joins hands with the passionate guard Jin Tianshuang and the street prodigy Little Mouse to form an iron triangle of investigation. The three people peeled off their cocoons and vowed to solve the mystery of the "Tianmu" before all the lights went out and protect the peace of the people of the Tang Dynasty.
