Just three years after the huge insect invasion that destroyed Houston, Brian Davis, the son of the late Maria Davis, is sleeping at night when he hears a noise. He goes out in his backyard to investigate, and, sees a giant snake eating a giant rat. His father comes out, and, along wiht the rest of the family, stays inside. The snake doesn't seem to notice Brian, and continues eating. Brian then sees his father's shotgun, but, before he can reach it, his father yells no, startling the snake. The snake then notices Brian, and leaps at him. Brian is thrown into the house, where he falls unconsious. His foster brother, Ben, calls the police, and tells them that Brian is hurt, not mentioning the snake. When the police arrive minutes later, they discover a bloody scene, with the house in ruins, and blood all over the place. One officer, Dale Winslow, sees a body covered in blood. He discovers the body to be of Ben, and, the reason he recognizes the body was because he worked with Michael Stevens three years before, before Mike died. The next morning, Dale discovers on the news with his family that the government had found some DNA from the animals buried in the beach near Houston, and they were mutating animals again, but, were keeping them under containment. But, the newscaster then says about the snake incident the night before. Dale then turns off the news, and, then is reported to downtown, but, before he can answer the call, he hears a loud explosion outside. When he gets outside, he discovers that a giant wolverine was eating a giant centipede, but, caused a tanker truck to crash into a house, causing the huge explosion. He reports with his family downtown, but, just as they reach downtown, a huge lizard leaps from the roof of a skyscraper, and crushes and kills many people. The lizard then is attacked by a giant mosquito. Dale gets the shotgun, and a grenade from the back of his trooper car, and, starts shooting at the mosquito. The mosquito then attacks Dale, and kills him and his family, but, then, the lizard attacks the mosquito, and kills it. Just then, Colonel Brian Valentine of the US Navy, gets out a grenade launcher, and shoots at the lizard. He causes a building to collapse on top of the lizard, crushing it, but, not killing it. The lizard then breaks free, and, attacks Brian. Brian shoots the lizard in the mouth, and it kills it. The lizard then explodes, and guts fly everywhere, along with bones and blood. When General Fred Jackson, of the US Army, stumbles over a piece of guts that came from the lizard's lungs, he finds a piece of paper, which is from Area 51. He discovers that more animals are being mutated at Area 51, but, before he can figure out what it is for, he is crushed by a piece of falling metal off of a building. He is killed before he can figure everything out.