Chen Meng is an ordinary security guard at Yunding Huating. When his sister encounters harassment from a property owner, he accidentally discovers construction safety hazards in the community's underground parking garage. An abnormal piece of rebar pulls out the past events of his brother-in-law's accidental death three years ago. As the investigation deepens, suspicious surveillance, elevator malfunctions, the mysterious thirteenth floor, and other doubts appear one after another, and the hidden secrets behind them gradually surface. Facing heavy obstacles, Chen Meng relies on his years of construction site experience to join hands with Gu Yunshu to find evidence, uncover the truth sealed for three years, protect the safety of residents, and seek justice for his family. In his ordinary position, he interprets responsibility and commitment with actions.