Return to Mysterious Island 2 begins with the crash of the helicopter that came to rescue Mina. She survived but is once again trapped on the island. All of a sudden, under her very eyes, an unknown disease afflicts the plants first, then the animal life. Mina explores the island to locate the infection source. She searches Captain Nemo's base in vain, then the ruins of an unknown civilization, and finally understands that it is outside pollution that threatens the island. The only way to save this natural wonder is to turn the shield back on. But if Mina makes this decision, she gives up - as Captain Nemo did before her - the idea of returning to civilization.