Transfer student Su Wan brings her father's psychology notes to her new class, hiding an unhealed wound beneath her quiet exterior. Then she meets Gu Yang, a boy as bright and cheerful as sunshine. He secretly warms her notebook with a plane-tree leaf bookmark and hides a bloodstained handkerchief where she can't see it. They use their warmth to thaw each other's winter, unaware that some promises are never meant to last until spring.
This is a story about redemption and regret, about two souls who shine a light for each other in the dark and use a brief spell of sunshine to warm each other's long, cold winters.
