A baby anaconda, which was captured at the end of the previous film, is being used for experiments by a man named Peter Reysner, who creates a hybrid of the blood orchids from Borneo that enabled the anaconda to grow so large and live so long, and creates a serum for cell regeneration. After the test seemingly works for the baby anaconda to regenerate, Peter burns it. When he disappears, the long anaconda escapes from the cage and kills Peter in a mine filled with blood orchids. J.D. Murdoch, a billionaire suffering from bone cancer, sends his assassin Eugene and his team of henchmen mercenaries to find Peter and the serum Peter created so that it can cure him. He also tells them to be careful of Dr. Amanda Hayes, and to kill her if needed. Dr. Amanda Hayes, the sole survivor of the previous snake attack, and two officers also go in search of Peter, determined to destroy the serum and kill the snake.
On the way they meet Alex, a trekker who appears lost in the Romanian Carpathians, while doing a pathology project. When they discover the blood orchids in the mine, Amanda sets the explosives to destroy the orchids, but she is attacked by the anaconda that kills two officers, but manages to evade it. As Amanda and Alex leaves the mine, Amanda is knocked unconscious and Alex escapes to get more help. Meanwhile, two groups encounter more people (Scott, Jackson, Patrick, Wendy and Heather) who are looking for the base camp of fellow scientists but get dragged into the search for the snake. Due to the serum, the anaconda can no longer die without significant damage to its internal organs. Heather falls ill due to a spider bite. The next day, most of the people are attacked and eaten by the snake. It first kills one of the hunters working for Murdoch. When Eugene and his henchmen find Hayes and Jackson's group, they capture them. Eugene shoots an already injured Patrick, and also shoots and injures Wendy for trying to escape.
The snake finds them and devours Leila and Hakeem. Amanda and Jackson are forced to find the serum, and are accompanied by two henchmen of Eugene to find it. They put up at Peter's house. There the two find the serum but keep it hidden. The anaconda strikes the house and devours one gunman, and while the other is trying to fight it off, Amanda and Alex escape. Jackie corners them, but is taken by surprise by Jackson. The snake attacks Jackie and he accidentally blows himself up with a grenade while trying to destroy the snake. It then chases Amanda and Scott. Scott sacrifices himself to the snake to buy time for Amanda to run. In an attempt to destroy the snake, Amanda throws a gasoline tank at the snake and blows it up, but the snake regenerates after she flees.
Back at the base camp, Murdoch appears, but is in for a rude shock when he sees that his arch enemy Vasile is also there, and that Eugene has joined ranks with the latter. Seeing the melee they are in, Jackson stabs Eugene, makes him shoot Murdoch's rival and then fights Armon, but Jackson gets shot and Amanda shoots Armon to death. Murdoch arrives, demanding that Amanda give him the serum. As they do that, he keeps his word and allows them to leave. As the remaining survivors leave in the jeep, Murdoch injects himself with the serum and discovers that it works, but the snake eats him. As Amanda finally destroys the orchids for good, she, Jackson, Alex and Heather try to escape in a jeep as the anaconda pursues them, but they are attacked by Eugene, who had clung on the back of the vehicle. Amanda kicks him out of the car with two grenades in hand. While the snake devours him, it is blown to bits. As Amanda, Jackson, Alex and Heather leave, the anaconda who seems to have regenerated, and slithers into the forest.Crystal Allen as Dr. Amanda HayesJohn Rhys-Davies as J.D. MurdochLinden Ashby as JacksonAna Ularu as HeatherEmil Hostina as EugeneDanny Midwinter as ScottCălin Stanciu as AlexAnca Androne as WendyAlexandru Potoceanu as Roland / PatrickClaudiu Bleont as ArmonDan Badarau as VasileZoltan Butuc as Peter Reysner
The film was shot back-to-back with Anaconda 3: Offspring in Romania (Bucharest, Danube Delta, etc.) When the film was first announced, David Hasselhoff was slated to appear to reprise his character of Hammett from the third film.
A total of 8 different types of firearms were used in this movie: handguns (5), submachine guns (1), and riffles (2).
DVD Verdict rated it 58/100 and called it "hugely boring".