"Due to an unexpected accident, Choi Yujeong, an ordinary college student, owes some money from the owner of a cafe called "Delicious Blood." Daniel, the owner of the cafe, tells Choi Yujeong to pay off her debts by working part-time at his cafe. Choi Yujeong eventually starts a part-time job, but the handsome boss Daniel, doesn't let her off the hook. Who is Daniel? And what will happen to Yujeong?"