Full-Scale Deduction: The Final Culprit

Ten years ago, Bao Na, a member of E University's Mystery Club, was murdered during a mystery salon. The crime scene was a sealed room, and the other seven members who attended the event couldn't remember what had happened. Everyone was a suspect, but there wasn't enough evidence, so the case went cold. The seven members graduated without trouble and went their separate ways.

Ten years later, the seven reunited. One by one, they received invitations and came to this grand unveiling. Once again, they were locked inside a sealed space. The objects that had pointed to each of them as having a motive ten years ago appeared before them again, forcing everyone to drop their masks. The mysterious person who had gathered them was hiding among the seven. They had to complete the tasks assigned by this person within seven days and find the real killer among them. Seven people, seven stories: who is lying?