Warm on a Cold Night Episode 5

Jiu Er and Han Zheng try to ascertain the identity of the body purported to be Official Zhang. During their investigation, Jiu Er finds the rare medicine only found in the Qi kingdom that her mother uses to help prolong her life. They also discover the name of the corpse, which leads them to a theatre playhouse where they encounter Wen Jun, the playwright of the story that uses the corpse’s name. (Source: frankly at MyDramaList)