The Purple Lagoon, the newest internet sensation on the resort island, has attracted many tourists, but the Purple Lagoon has swallowed several of them. When the only daughter of the richest man in a Southeast Asian country goes missing for no apparent reason, war correspondent Bai Yu investigates and biologists and "crocodile hunters" confirm that the richest man's daughter has died in the mouth of a crocodile. The richest man vows to hunt the crocodile at all costs to avenge his daughter's death.

After the “September 18 Incident” in 1931, Japanese forces occupied Northeast China. University student Bai Yihua was ordered to return to his hometown, Liaoyang, posing as a teacher to secretly organize anti-Japanese resistance. However, constant threats put his mission and identity at risk. As enemy and ally clashes intensify and his cover nears exposure, can Bai Yihua uncover the traitor, break through the siege, and turn the tide of the resistance?