Cutter now has conclusive evidence that someone has been shadowing the team and interfering in the past. His and the team's suspicions now fall on Lester and Jenny. He is determined to prove that one of them - or perhaps both - is the traitor but his plans are interrupted when an anomaly is detected and Lester's worst nightmare comes to pass - a giant Columbian Mammoth has appeared and is rampaging on a section of the M25 Motorway in broad daylight, scattering cars and sending pedestrians running for their lives. Cutter and the team respond but Stephan is nowhere to be seen...
Dealing with the confused and angry Mammoth requires every ounce of Cutter's ingenuity but when the anomaly closes, Cutter faces an even greater problem - how do you hide a Mammoth? With the press about to break through the cordon Jenny has erected, Cutter formulates a new plan and with the help of Connor and Abby manages to trap the mammoth in the back of a lorry.
The team get away with it by the skin of their teeth (though Jenny has to deal with the aftermath, namely in the form of unscrupulous journalist Mick Harper sniffing around for a story), but Cutter is bewildered and angry with Stephen when he finally turns up, too late to be any real help and with no convincing explanation for his absence. To make matters worse, Stephen has brought Helen with him (Helen is still, unknown to him, manipulating Stephen for her own ends, convincing him Cutter and Lester are at the heart of the ARC's troubles). Cutter refuses to talk to either of them, abruptly firing Stephen and dismissing any notion Helen has come to help. Back at the ARC, Stephen attempts to bring Abby and Cutter around to his way of thinking, but Abby stands by Cutter's decisions, and Cutter refuses to even listen to him. Furious, Stephen calls Cutter arrogant and stubbourn, snidely remarking "No wonder Helen turned to me!". Outraged, Cutter punches Stephen in the face and orders him out of the ARC. With one problem dealt with, Cutter sets off to track down the enemy within. He sets a trap, letting only Connor and Abby in on his plan. They install a virus into the ADD to sabotage whoever is hacking into the system, then fake the appearance of an anomaly on the detector to see who will go to it first, knowing that whoever it is must be the traitor. The plan works, and reveals that the traitor is... Jenny.
Cutter is badly shaken. When he confronts her, she claims to have no idea what he is talking about - she received an anonymous text telling her to meet him there. With Cutter holding a gun to Jenny's head, and the soldiers with her ready to cut him down, bloodshed seems inevitable. Jenny ultimately reveals that it was actually Leek who sent her: Cutter deduces that he is the traitor, having set up the innocent Jenny. Not only that, Leek has somehow smuggled a Future Predator into the ARC and set it loose. The predator has already killed much of the ARC's staff, leaving only Lester. Leek contacts Lester, taunts him and then somehow commands the predator to kill Lester.
After a harrowing chase through the deserted corridors of the ARC, a wounded Lester flees into the ARC's gym, where he is able to jam the predator's echolocation with music from a stereo, distracting it long enough for him to arm himself with a machine gun. After a brutal battle in the ARC's armoury, Lester retreats to the Operation Room, with the predator in hot pursuit. Out of options and with the future predator right behind him, Lester angrily tells Leek he won't beg for his life and derides Leek as "a tiresome little man!". Furious, Leek orders the predator to kill Lester, who simply waits for the deathblow. But just before the predator tears him to shreds, the mammoth (which Lester had released seconds before), charges in and impales the predator on its tusks.
Once the team return,they try to hack into leeks files after guessing the password they find theres a bomb that has been acctivated in the ARC. Leek had set a trap on the ADD that set off the bomb, Nick and connor despretley try and defuse the bomb with no luck. At the last minute Cutter rips out the car that the bombs under's battery stopping the bomb. Lester tells his security force officers to find Leek and arrest him. Unfortunately, Leek has set a false trail for Lester and his soldiers, and they only find a dead end. Meanwhile, Cutter and Abby, with Cutter and Jenny in tow, track down Caroline to a disused MOD base, hoping to recover Rex. Leek, however, is waiting for them and he captures the team: Cutter and the others are knocked unconcious. When they come around, they are in a dark room, lit by ominous red light. Cutter and the team are not alone: with them is Leek...and Helen. As the revelation that Helen is in league with Leek sinks in, the lights return to normal and the team take in their surroundings with growing horror. As Helen flashes an evil smile at the group, they see Leek has acquired a menagerie of creatures from different times, including Coelurosauravus, Scutosaurus, Arthropleura , Raptors , Smilodon , Mer Creatures , and Silurian Scorpions .