On the eve of a public archive's opening, a blue archive box vanishes from the central display stand. Rather than assigning blame on suspicion, Yan Cheng and Qi Yue verify the facts step by step through access cards, surveillance footage, and witness routes, ultimately locating the original documents that Li Shuo had moved without authorization. Li Shuo admits he concealed what happened because he feared exposing his own filing error, and is willing to take responsibility. The team completes a two-person review, confirms the contents are intact, and closes the procedural gaps so the exhibition can open on schedule. The incident teaches everyone that mistakes are not to be feared: only by communicating promptly, respecting the rules, letting evidence speak, and sharing responsibility together can trust and accountability be upheld.