Ye Cheng, who was down and out, met Bai Yu, a young girl who lived alone who was inexperienced in the world, on a rainy night. He spent all his savings and moved into her old rental house. While taking care of Bai Yu, who lacks common sense in life, and teaching her to integrate into daily life, he gradually learns the secret past of the girl who was imprisoned by her mother for many years. The door locks that are frequently maliciously corroded also create hidden crises in their lives. Two ordinary people who are at the bottom of their lives become each other's salvation through the trivial interactions.
