Season 4 - Episode Guide

Connor and Abby struggle with life in the Cretaceous Period, meanwhile the A.R.C. has been rebuilt and updated with two new members.

When Connor looks up old friend Duncan, he doesn't expect to find him obsessed with creature sightings. Warning him of the elusive dock creature, the pair track it down to the docks, only to find evidence of a fresh kill. With Abby and Matt arriving to help, they find the creature after a tense chase through a container yard. Will Connor's quick-thinking and bravery earn him back his place on the team?

A mysterious group come through an anomaly in a theatre, unknowingly followed by deadly tree creatures. As they attempt to escape, Matt inadvertently brings one of the group - Emily - back against her will. She promises to help him find the creature, in return for going back through the anomaly. In a frantic chase through the city, they track the creature down, only to discover the anomaly has closed, leaving Emily stranded.

Whilst Abby is arguing with Burton,who wants to kill the menagerie,the team gets called to a school where a Therocephalian has come through a gateway and killed a young teacher. Unaware of his fate two nerdy boys in weekend detention accidentally lock the school's security system so that the ARC lads are unable to reach the anomaly. By the time Connor has rectified the system a a whole tribe of the creatures appear and have to be killed with a smoke bomb. Sir James stops Burton from disposing of the animals,making him Abby's hero though she is annoyed at Connor's lack...

Abby and Connor travel to coastal Witchfield Cove,home to the legendary giant worm,after the death of a camper. They find the worm is no myth but a Labyrinthodont,come through a portal in a cave,accidentally opened by a farmer and her son,tipping waste acids. After its disposal Connor accepts a role in Burton's secret project. Matt traces Emily via the black box he has given her and saves her from being buried in a vault,the former burial place of Ethan's sweetheart Charlotte. However Ethan escapes .

Doglike Hyenadons come through an anomaly in the basement of a stately home and when the team go to investigate they meet ex-ARC worker Jenny Lewis,who is about to get married in the hall. It is a true epiphany for Jennifer's groom,unaware of her background,as he and other terrified guests watch Jenny and her old colleagues push the creatures back through the portal. Jess saves Becker from being killed by a booby trap rigged up by Ethan,whose police record from 1900 shows him to be a wanted assassin and anarchist in his own time. Matt learns that Emily was once the ...

The ARC team gets called to a prison where they find themselves unable to control the anomalies and suspect that Ethan is manipulating them. Suddenly Danny emerges from one of the worm-holes and it transpires that Ethan is his brother Patrick,who went through an anomaly as a boy and for whom Danny has been searching ever since. He had assumed the name Ethan and appeared in different time schemes to wreak havoc and,as he returns through an anomaly,Danny goes after him to keep an eye on him. Before this Danny has warned that Burton knew Helen Cutter and is not to be ...

Five webisodes were released from 22 December 2010 in the run-up to the fourth series, which began airing on New Year's Day 2011 in both the UK and US.

ITV released the webisodes, each 2–4 minutes long, written by Sarah Dollard, that provided background to the upcoming series 4.