Kalifornialaisen pikkukaupungin asukkaat joutuvat kuolemanvaarallisten hämähäkkien hyökkäysten kohteiksi, ja kahden lääkärin on keksittävä keino päästäkseen eroon kahdeksanjalkaisista tappajista, ennen kuin ne valtaavat koko kaupungin.

Yksi luikertelevista geneettisesti muunnelluista anakondan jälkeläisistä on herännyt henkiin tässä vauhdikkaassa Anaconda-sarjan osassa. Kuolemaisillaan oleva moguli Murdoch palkkaa tiedemiehen kokeilemaan elvyttävän nektarin vaikutusta pikku käärmeeseen. Vuorokauden sisällä käärme on kasvanut hirviöksi ja sen ruokahalu kasvaa riittävästi tiedemiehen ahmimiseen kokonaisena. Anakonda karkaa tuhoisalle pakomatkalle. Hemaiseva matelija-tutkija Amanda yrittää tuhota itse luomansa pedon kokoamalla nuorten tiedemiesten ryhmän, joka joutuu taisteluun niin geenihirviötä kuin Murdochin aseistautuneita roistojakin vastaan. Verenhimoinen matelija näyttää olevan voittamaton ja syö kaiken tielleen osuvan.

Africa in the sixties. The Nile perch, a ravenous predator, is introduced into Lake Victoria as a scientific experiment, causing the extinction of many native species. Its meat is exported everywhere in exchange for weapons, creating a globalized evil alliance on the lake shores. An infernal nightmare in the real world that wipes out Darwin's Theory of Evolution.

In 1890, one man had the idea to collect every bird ever mentioned in Shakespeare and release them into Central Park. The only bird to survive in the New World was the European starling, which became one of the most common birds in North America. Its introduction is now widely considered a major environmental disaster.

After decades of hurricanes and oil spills, Louisiana faces a new threat - hordes of monstrous 20 pound swamp rats. Known as "nutria", these invasive South American rodents breed faster than bounty hunters can "control" them. With their orange teeth and voracious appetite they are eating up the coastal wetlands that protects Thomas and his town of Delacroix Island from hurricanes, but the people who have lived here for generations will not give up without a fight.

Cats are cuddly felines and lovely pets, but also highly evolved predators that hunt huge amounts of small mammals, birds and reptiles; perfect killing machines that threaten delicate ecosystems around the world.

In 1940 twenty Canadian Beavers were brought to 'Tierra del Fuego' island in southern Patagonia for commercial fur production. However, beavers having no natural predators, quickly spread throughout the island, causing massive destruction of trees threatening the entire Patagonian forests rivers and species. Why wildlife conservationist are convinced that 150.000 beavers must be killed? Why some of the most recognized specialist are convinced that an eradication is not possible? Meanwhile truism is capitalizing on the situation: a man dressed as a beaver passes out flyers promoting a famous sky resort: 'Cerro Castor' - Beaver Hill. Hunters claim for subsidies, scientists are researching, rangers do what they can and restaurants tray to offer beaver meat to tourist.