Han Hae Na is a single high school teacher with a family secret. Due to an ancestor's fault, Han Hae Na's family has been cursed for generations. When someone of her family kisses anyone, they turn into a dog at midnight for six hours. Afterwards, they revert back to their normal appearance. This transformation repeats itself every night until that person, in their dog appearance, kisses the same person. Whenever Han Hae Na meets a man for a potential romantic relationship, she asks that person to not kiss her. This usually leads the men to leave her. Drunk one night, Han Hae Na accidentally kisses Jin Seo Won, a teacher at the same high school, though they aren't even close as colleagues. Han Hae Na soon panics and persistently approaches Seo Won for a chance at another kiss. However, Jin Seo Won has a fear of dogs.
