Ritsch and Jooin, a prince and a son of a gardener, have grown up together since childhood. Jooin has had a crush on Prince Ritsch for a long time. But, it is certain that the Royal Prince, who is an Alpha, will be marrying an Omega and succeed to the throne. Jooin, a Beta and a commoner, is aware that he cannot connect himself to Prince Ritsch. Eventually, Jooin take no notice of Prince Ritsch's request to stay by his side for the rest of his life as his Dongsaeng -- 3 years later, being unable to completely remove Prince Ritsch from his heart, Jooin returns to the castle to reunite with the Prince as a butler this time. On the other hand, Prince Ritsch has never looked for Jooin who left the castle. Jooin thought that they wouldn't be able to return to the relationship they had before. However, with Prince Ritsch's concealed demeanor, Jooin gets more and more involved with him...