An anomaly opens in a theater. Through it come three people. They are part of a group known as the Time Tribe. One of them, Charlotte Cameron (Sara James), is injured and soon dies. The other two are Ethan Dobrowski (Jonathan Byrne) and Emily Merchant (Ruth Bradley). They are from the 19th century. They have been stuck in the Cretaceous period and are trying to get back to their own time. Ethan is mentally unstable. Also, through the anomaly come two Tree Creepers.
When the anomaly alarm sounds at ARC Abby (Sarrah Spearritt), Becker (Ben Mansfield) and a team of soldiers are sent. Matt (Ciaran McMenamin) is called to meet them there. Matt gets to the theater before the others. When he sees Emily return through the anomaly he goes in after her. When Abby and Becker get to the theater, they lock the anomaly. When Abby realizes that Matt went through the anomaly, she tries to convince Becker to open it again.
Back at ARC Philip (Alexander Siddig) makes Connor (Andrew Lee Potts) stay to test out a new lockdown system that Philip created. The system is designed to lock down the facility if one of the creatures manages to escape. While walking through the facility Philip notices that Rex, Abby’s pet Coelurosauravus, is wandering around. Rex triggers a lockdown and Philip ends up locked in with Rex. Everything else in the facility shuts down. Philip is the only one who can terminate the lockdown, but he is unable to get to the main terminal. The room with Philip and Rex is slowly having the air removed. If Connor can’t find a way to bypass the system, Philip will die.
Episode 3 of season 4 features Tree Creepers. Tree Creepers were an arboreal raptor from the Cretaceous period. They spent most of their time in trees and were adept at moving from tree to tree. Their prehensile tails helped them to movie through the tree canopy. Their name came from the Time Tribe.
The Time Tribe is a group of people who have become lost through various Anomalies and have banded together. They travel through the anomalies in search of their respective time periods.