I’m a maid of a vampire duke?! Areum Yoon, a normal high school girl, falls into a strange isekai world called 'Soltera' after an accident. She is sold as a slave to Millard Travis, a duke and the only vampire in the world. Desperate to survive, she swears to serve the cold-hearted Lord Millard as his personal maid. Will Lord Millard's attitude change with Areum's devotion to him?