Is there anything more terrible than having a crush on your boss when you are a secretary? Yeon Woo used to be a beta but he turned to omega because of the strong Alpha pheromones from Keith who is his boss now. However, Keith is one of the sexist Alpha with tons of omega around and especially he rejects male Omega. Just when Yeon Woo thought that his one-sided hidden love would come to an end in vain, he discovered that Keith seemed secretly taking care of him and hiding his complicated feeling for Yeon Woo. And their relationship turned to a new level on the day Keith lose his mind when the period was coming..