In the "echo chamber" of an abandoned sanatorium, nine seemingly unrelated professionals were trapped for seven days and forced to take turns recounting the stains in their lives that they had hidden for ten years. The greed of lawyers, the perjury of doctors, the price of journalists, the sins of developers, the silence of teachers, the cover-up of the police... As the truth was revealed layer by layer, they were horrified to find that everyone's "unintentional mistakes" were intertwined like a butterfly effect, forming a systematic net that swallowed up innocent people. The ninth mysterious visitor is the designer of this trial - for all the "forgotten names" sacrificed by the system, a final trial about guilt, awakening and redemption, ushering in a subversive ending when the bell rings on the seventh night.
