A young girl named Taylor (Mabel Rogers) chases after her runaway dog and straight into an anomaly. At the same time the anomaly detector at ARC sounds an alarm. It stops almost as soon as it starts. Nick (Douglas Henshall) thinks there is a problem with the equipment, but Connor (Andrew Lee Potts) determines that the computer has been high jacked by spyware. Connor assumes that it was The Cleaner (Tim Faraday) that did it. In reality, Oliver (Karl Theobald) diverted the signal and The Cleaner works for him. Oliver locates the anomaly and sends The Cleaner and a few other special ops people into the anomaly to capture any animals on the other side.
Nick uses a handheld version of the detector to find the anomaly. They send in a remote homemade camera robot, that Connor put together to see what is going on. In the distance, on a rock, they see Taylor. Nick and Stephen (James Murray) have no choice but to go into the anomaly and try to save her. They find themselves in the Silurian period. They also find what is left of the Special Ops team. Taylor begins waving to them, but they can’t hear what she is saying. Suddenly, a swarm of millipedes shimmers by them. Then the ground beneath them begins to move. Something under the ground is hunting them. Nick and Stephen run for the rocks. When they reach them, and Taylor, they turn and see the anomaly slowly closing. Now they are trapped on a rock in the Silurian age with a Silurian Scorpion under the sand.
Episode 5 of season 2 features Silurian Scorpions and Silurian millipedes. A Silurian Scorpion is a species of giant scorpion from the Silurian period. They are arachnids. They hid under the sand and tracked prey by sensing vibrations. They would then drag their prey under the sand. Silurian Millipedes are millipedes that lived during the Silurian period and are arthropods. They were the main food source for Silurian Scorpions. They look similar to modern day millipedes only much larger.
Leek has been using The Cleaner and his soldiers to capture any anomaly creatures they can find. I’m not sure how many animals Oliver expected The Cleaner to catch with a small crate, a dog catchpole and a machine gun.