One day, an ordinary college student, Choi Yoo-jeong, finds herself into debt to a cafe named 'Delicious Blood' because of an accident. A huge debt of 100 million won. Daniel, the owner of the cafe, tells Choi Yoo-jung to pay off her debt by working part-time at his cafe. Choi Yoo-jung eventually starts working, however, Daniel, the handsome boss, doesn't wish to let her go. And slowly Daniel becomes close to Choi Yoo-jung because to him, she smells sweet. What exactly is Daniel’s identity? And what will happen to Choi Yoo Jung’s future?