On an island off the California coast it's the Fourth of July. Tourists are washing up dead on the shores of Babylon Bay. In 1987, rumour had it that underwater sea monsters known as Aquanoids were responsible for 17 vicious deaths. In order to protect the local tourist trade the Mayor downplayed the sightings as urban legends. Environmental activist Vanessa Dumont's struggle to save the endangered abalone species on Santa Clara Island turns into a fight for her life. Will she save the island inhabitants and visitors from the latest Aquanoid attacks? Or will the avaricious locals permit more innocent people to be slaughtered?