Princess Agent 楚乔传 sounds like it could be a marriage of Rookie Agent Rouge and every other period drama starring Zhao Li Ying because this time around, she plays an agent stuck in ancient times. Given Zhao Li Ying's numerous projects for the past years, I seriously wonder how she manages?
Princess Agents will star Zhao Li Ying (Legend of Chusen), Lin Gengxin (God of War Zhao Yun), Shawn Dou (Tribes and Empires), Li Qin, Deng Lun (Because of Meeting You), Maggie Huang (Eternal Love), Niu Jun Feng (Just One Smile is Very Alluring) and Alan Wang Yan Lin (Monster Killer).
Based on the novel titled Queen of No. 11 Agent by Xiao Xiang Dong Er 潇湘冬儿, the story revolves around an agent who is killed in action and time-travels into the body of a slave girl during the Xia Dynasty, no doubt accomplishing great deeds in her time. However due to censorship, the story will most likely be tweaked to remove time-travel completely.
You can also check out the set of Princess Agents (article from cpoplove).