I read the story of this song in another you tube comment in Chinese and has translated it to English. This song is about the story of a bird and a cicada. The bird met the cicada in the summer, and they spent the best summer together. They made a wish on the empty bottle: autumn is coming, and the bird is about to fly away. It said to the cicada, "I am going to fly away, but I will return next summer to see you." The cicada said, “I can't meet you next summer. I will appear in the fifth season. The fifth season starts in the 13th month. You must appear as scheduled at that time.” The bird flew away but didn't know that there is no fifth season in human time, and there is no thirteenth month. The cicada's life ended in that summer but wanted the bird to leave with ease. The Bird flew across the long northern latitudes in the winters of December and returned, but it never flew to the fifth season, nor the thirteenth month. The bird is still flying back & forth because it remembers the promise they made together in that summer.