There is a "Heart Time Inn" in Harbour City. This small inn has a small marketing method. As long as couples stay here and write a letter to each other, they can use the card to take out the letter written by the other party two years later, and they can also get a free room. Xiaoya (played by Ye Qing), Aunt An, and Uncle Afu are the owners of this inn. Xiaoya also has two good friends in the harbor, the radio music DJ Allen (played by Wu Yi) and the little beauty Tang Guo (played by Kan Qingzi) in the yogurt house. One day, a mysterious guest, Martin (played by Mario Maurer), moved into the inn. This handsome and sunny boy has charming eyes, a big stomach that is inconsistent with his appearance, and super strong strength. Xiaoya, Tang Guo, Allen and Martin who lives in the inn became good friends and knew the purpose of Martin's visit to the inn. It turned out that Martin brought the "time card" left by his mother 20 years ago to the inn to get the letter from his parents that year and knew who his father was, but the letter from 20 years ago was gone. Xiaoya falls in love with Martin, who may leave at any time. In order to help Martin find out the truth about his parents, Xiaoya and Tang Guo take action. Unexpected results appear in front of everyone. What is the relationship between Uncle Afu and Martin? Martin and Xiaoya love each other but feel that the other is not suitable for them. Can they be together in the end?