Come Back, My Real King

Elena is empress, married to the emperor for three years. She believes he is the man who once saved her life, and she believes he loves her. Her cousin sets her up and she is left in a ruined temple, where she ends up in the hands of Adrian, the regent. Adrian was the one who saved her. The emperor took the credit to hold on to imperial power, and he has been holding Elena's father and brothers prisoner. Her cousin had a hand in stealing her medical formula as well. Adrian tells her what he knows, and Elena begins working again, rebuilding her strength and her skill as a physician. She develops a treatment during a plague. She had been a piece on someone else's board and she stops being one, and she goes after her cousin and her husband in front of the court.