The Emperor Is Afraid That the Princess Will Have the World

In her past life, she was a superb beauty and a deadly killer, but that all changed when she was murdered by her own friend. Luckily, god gave her another chance. She was reborn into ancient times. She regained her youth only to have her blood sucked by this vampire?! Why?! To save him from poison? Who would believe that! Is this some sort of joke?! That demonic man really threatened her with poison, and he even wants her to go spy for him in the palace! A modern assassin in a dangerous palace. Will she help this evildoer complete his revenge and find the antidote? What secrets lie inside the gorgeous palace?