Professor Nick Cutter and his team are investigating the sighting of what seems to be an extinct dinosaur. They travel to the Forest of Dean, where it was seen, to explain how it appeared and discover an even stranger phenomenon, while the escaped creature is on a hugging spree.

In the London Underground, a cleaner is fatally bitten by a gigantic spider. Nick Cutter's team is sent to investigate. In their search, they discover a maze of unused tunnels, and come nose to nose with an even more frightening creature.

Swimming pools, inner-city reservoirs, and flooded cellars in suburban homes are being overtaken with prehistoric reptiles, which have all come through the space-time anomalies. The gang go to investigate, but Nick is more concerned with finding his wife.

Nick discovers that a group of dodos are carrying a deadly ancient parasite that could have devastating consequences for the human population. Meanwhile, Helen is back in the 21st century, and being interviewed by the Home Office, although she isn't being as cooperative as they hoped.

A prehistoric winged reptile arrives through an aerial time rift on a golf course. Nick goes to investigate, but he ends up trapped in the hotel with Claudia. Elsewhere, Connor loses Rex, much to Abby's anger and both are stalked by malicious flock of prehistoric flying raptors.

Helen returns and claims that a predator from the future is behind a number of disappearances. Nick and Helen join together on a desperate race through time to prevent further attacks, and discover a shocking truth.