Since I Don't Know About It, Should We Part Ways, Your Majesty?

Due to a carriage accident, Lumiere suffers from amnesia. While searching for her memories, she discovers a warning in her diary. [Do not fall for him.] At that time, a man claiming to be her lover appears. "I know everything about you, even the parts you don't know yourself." This man, who doesn't exist in her memories. But she finds herself increasingly attracted to him... ...Were we really lovers? Why did we break up? Is approaching the truth really the right thing for me?