A young architecture student suddenly has to live with a ghost who has lost his memory. From the confused early days, they gradually embarked on a journey together to find a piece of the past. In the midst of everyday life, they rely on and protect each other, and an invisible bond gradually becomes deep... But that love has to face an insurmountable distance - the boundary of yin and yang. A story that is both warm and endless, about friendship, love and even things that have not yet been said.