Tras un año atrapados en el cretácico, Abby y Connor finalmente retornan al presente, seguidos por un gigantesco Spinosaurus, el mayor dinosaurio carnívoro conocido. El nuevo equipo ARC reacciona.

Connor y un viejo amigo rastrean a un elusivo Kaprosuchus (Cocodrilo-jabalí) hasta los muelles donde encuentra evidencia de una muerte reciente.

Un grupo misterioso llega por una anomalía a un teatro, seguidos sin saberlo por tres mortales criaturas. Cuando intentan escapar, Matt inadvertidamente trae a una del grupo, Emily, de vuelta en contra de su voluntad. Ésta promete ayudarle a encontrar a la criatura, a cambio de volver por la anomalía. En una frenética persecución por la ciudad, consiguen rastrear la criatura pero descubren que la anomalía se ha cerrado, dejando a Emily atrapada.

The team go to investigate a flunctuating Anomaly signal at a seaside village, and Matt and Abby struggle to contain a fast and deadly Labyrinthodont's rampage while Connor tries to uncover the secret behind the fluncuating Anomaly signal. Meanwhile, Emily has been captured by Ethan, and Matt attempts to track and save her before it's too late.

The team investigate an Anomaly incursion at a rural manor house, and reunite with Jenny and discover that the manor is the location for her wedding in the morning; forcing the team to contain a pack of Hyaenodon while ensuring Jenny's soon-to-be-husband doesn't find out. Meanwhile, Jess and Becker are caught in Ethan's deadly trap.

The team head to an old prison, where they discover an Anomaly that won't lock and is producing satellite Anomalies throughout the prison, which in turn makes it even harder for the team to track a Terror Bird loose in the prison. At the same time, Danny returns from the past with a warning for the team, Ethan's true identity is discovered, Emily is torn between Matt and the chance to return to her home, Matt reveals his secret, and Connor makes a terrible discovery.