A river was polluted, and some human tissue was found downstream, so the Water Conservancy Bureau sent Aaron and a team of explorers to investigate the source of the pollution. Bryan went up the river to look for bodies. After setting off, the expedition team spent a night in a wooden house that had been abandoned for many years. After waking up, Aaron found that the other team members were missing strangely, and a videotape in the wooden house recorded the clues of the whole story.