The story goes something like this - two men working together to protect four sacred objects in order to uphold the peace between two worlds. Bai Yu (Just One Smile is Very Alluring) heads an investigative bureau while Zhu Yi Long (Border Town Prodigal) is a mysterious man in a black cloak. Their journey is described as transcending life and death and time itself.
I honestly don't know what that means, I clicked because of the actors. It is based on a web novel by popular BL writer Priest so expect some heavy bromance (likely toned down to avoid censorship). Filming begins this April in Shanghai.