🗒️ Su Lin grows up neglected by her parents but remains determined to build a better future. After a confrontation with her classmate Ma Na, she accidentally falls into an underground pipeline and disappears. Around the same time, three female bodies are discovered in the city's underground river, triggering a major investigation.

🗒️ As retired police officer Gu Hao and student Jiang Ting search for answers, Su Lin's disappearance becomes closely connected to the murder case. Together, they uncover the dark secrets surrounding her fate and the mysteries hidden beneath the city.