"The sunshine of happiness is always lavender" is such an innocent sentence, a girl with a smile as bright as the sun, moved Xu Yanfeng, who was lonely and cold in his heart, in the most beautiful season, and the straw ring under the cherry blossoms brought them closer to each other's hearts. But he never thought that a sudden fire would turn everything into ashes, shattering the young man's longing and expectations. When I met my childhood friend again, things had changed. The girl Zi'er who had a bright smile back then has now lost her memory because of the fire, and she is so calm and melancholy. Just when Xu Yanfeng wanted to protect Zi'er with his life, a girl named Li Yutong appeared in his world with a bright smile! The sentence "The sunshine of happiness is always lavender" disturbed Xu Yanfeng's heart. Where will this emotion go? What kind of connection are there between Zi'er and Li Yutong when they were children?