Professor Nick Cutter
A professor of archaeology, and the leader of the team for the first two seasons
. A little off-the-wall, not to mention a host of issues relating to his wife, Helen. Played by Douglas Henshall.
One of Nick Cutter's students. While not initially the most reliable person, Connor is highly intelligent. He's been maintaining his own database of prehistoric creatures for years, and he developed pretty much all of the ARC's technology (save the EMDs). He moves in with Abby partway through Season One, and later enters a relationship with her
A zookeeper who joins the team in the first episode. Abby's primary contribution is her acute understanding of animal behavior and psychology. Enters a relationship with Connor, and proposes to him at the end of Season Five
- Action Girl
- Berserk Button: Rex.
- Broken Bird: Debatably. The Cretaceous seemed to have a more marked impact on her than it did on Connor. After her return, she rarely shows emotion anymore. The exception is with Connor, as their relationship was only strengthened by their shared adversity.
- Expository Hairstyle Change: Her hair grows longer while she and Connor are stuck in the Cretaceous, and she keeps it that way, marking her much cooler demeanor.
- Hospital Hottie: Abby is a qualified vet.
- The Lancer
- Mama Bear: To Rex.
- Spiky Hair: In season 3 when she really becomes an Action Girl. Apparently in real life, the bleach from the previous two seasons had fried Hannah's hair so it was only just growing back.
- Tomboy: Subverted. While Abby does have some tomboyish habits, she has several Girly Girl qualities as well. She loves a good Chick Flick, getting dressed up and cute animals.
- Tsundere: Abby occasionally acts like this towards Connor.
Cutter's TA. Served as the show's resident Badass for the first season. Turns out to have had an affair with Helen in the past. Dies at the end of Season Two.
An agent from the Home Office. Vanishes at the end of Season One, due to an apparent alteration of the timeline.
A PR specialist who joins in Season Two. Her main job is to take care of covering up the anomalies.
- The Chick
- Disposable Fiancée: Her fiancee in season 2 makes a brief appearance and it's not long before she gets cold feet and backs out of it. Averted in season 4 where she marries her new fiancée.
- New Powers as the Plot Demands: A justified example. She reveals she knows how to shoot a rifle a few episodes in. It's reasonable to suggest she didn't reveal that skill earlier because she was still getting used to being in situations where it would be useful.
- Opt Out: Resigns and leaves midway through Season Three, after nearly being killed by a fungus creature.
- Slipknot Ponytail: A few times in the second season, to show how out of her depth she is.
A government minister who is the official head of the ARC.
- Berserk Button: Do not try to usurp his authority, or he will use his many connections to bring you down. Also do not harm his Jaguar, as he will come after you with an EMD.
- An understated bonus point: don't try to usurp his authority while simultaneously implying that the genius he's a bit of a Team Dad towards should fetch you coffee.
- Da Chief
- Deadpan Snarker
- Jerk with a Heart of Gold
Nick Cutter's wife, who vanished through an anomaly eight years before the show started.
Veteran soldier, joins the team in Season Three.
An archaeologist who joins the group in Season Three, with the idea of tracking monsters through history.
- Aesop Amnesia: Complains in 3.7 that she is never allowed to participate in missions. She got over the trauma of what happened in 3.6 pretty quickly.
- Affirmative Action Girl: Her addition in season 3 brought the main cast of females up to four.
- McLeaned: Between seasons 3 and 4. Actress Laila Rouass opted not to move to Dublin to film as she didn't want to leave her young daughter.
- Politically Correct History: Played with. The boy she meets in the Middle Ages does ask first if she's a witch and then if she's from the Holy Lands, obviously not used to seeing a mixed race woman before.
- The Smart Guy: An additional one as that role was previously filled by Connor. Sarah's intelligence stems from her knowledge of mythical creatures and how they could be traced to real-life prehistoric beasts.
- Stay in the Kitchen: Protests against this in 3.7
- Tomboy and Girly Girl: After Jenny left, she filled the Girly Girl contrast to Abby's Tomboy.
- Twofer Token Minority: Was cast to appease complaints on the lack of ethnic casting on the show.
A police officer who gets caught up in the ARC's activities in Season Three, and decides to join without asking permission. After Cutter's death
, he becomes the new leader of the team.
Takes over the team after Season Three. Actually from the future
- The Hero: Although at this point, he's just the team leader.