A car accident is the reason why Lu Miao suddenly has a new older brother in Jiang Haoyue. Lu Miao practices various martial arts and becomes the female knight to Jiang Haoyue’s fallen prince. Similarly, Jiang Haoyue stands by Lu Miao to guard her in his own way. For Lu Miao, Jiang Haoyue is the moonlight that she has spent her entire youth chasing after, but the moon gets its light from the sun. Without her knowing, she is the sun that illuminates Jiang Haoyue’s whole world. As Lu Miao enters high school and makes new friends, she gradually realizes that her feelings for Jiang Haoyue go beyond that of siblings. Shi Che’s arrival brings upon a strong sense of unease for Jiang Haoyue. Soon enough, the brother and sisterly love evolves into young love.