An super-cool handsome guy is going out with me! But his blood type is "B"... what the hell! Ha-mi is a college student who believes in predestined love. One day she meets Young-bin on the street and instantly feels that he is the one. However, Young-bin is such a heartthrob and his blood type is "B", which is believed as the must-avoid type by many women! Despite her cousin's objection, Ha-mi falls for him because of his aggressive wooing.