The Forest of Dean is an area of woodland covering 27,000 acres. The Forest lies between the rivers Wye and Severn in the western part of Gloucestershire and on the borders of Wales and Herefordshire.
At some point in the 1990s or early 2000s, a Smilodon cub presumably came through an Anomaly from the Pleistocene, and was found by Valerie Irwin in her garage in the Forest of Dean and secretly raised there by her. (Episode 2.3)
Circa 1998, an Anomaly to the Permian opened in the Forest of Dean, and a Gorgonopsid came through. It chased Helen Cutter to an Asda in the Forest, and Helen escaped into the Permian through the Anomaly. Over the following years, the Gorgonopsid presumably guarded the area of the Forest of Dean where the Anomaly was as its territory. (Episode 1.1)
Eight years after Helen went into the Permian, a Scutosaurus and a Coelurosauravus named Rex came into the Forest of Dean through the Anomaly, and Rex was found by Ben Trent. Ben and Abby Maitland went into the Forest of Dean with Rex, and Nick Cutter, Stephen Hart, Connor Temple and Claudia Brown also searched the Forest for evidence of the Gorgonopsid. When Ben fled back home, Abby, Cutter, Connor, Stephen and Claudia found the Scutosaurus, which led them to the Anomaly.
The Anomaly site was subsequently secured by the Home Office, and Cutter and Captain Ryan went through with Rex on an exploratory mission. Rex, Cutter and Ryan returned to the Forest of Dean in the present through the Anomaly just before it closed, and the Gorgonopsid then attacked until Stephen arrived in a truck and killed the creature by gunning it down.
Following the Anomaly incursion in the Forest of Dean, Claudia Brown had Captain Ryan completely clear the area and left him incharge of mopping up the Anomaly site.
The Forest of Dean Anomaly reopened, and Helen Cutter escaped through to the present followed by a family of Future Predators. The Home Office team subsequently searched the area for any signs of the Predators, but found no tracks and so assumed that the creatures had gone back through the Anomaly.
Some days later, Nick and Helen led a mission through the Forest of Dean Anomaly and into the Permian to find and contain an Anomaly there to the future, while the rest of the Home Office team waited at the Anomaly site in the Forest for Nick and Helen to return. The mother of the Future Predator family also slipped past the team and through the Anomaly to get its young back.
Nick and Helen both eventually returned through the Anomaly to the Forest of Dean in the present, but Helen went back through into the Permian when Stephen refused to join her.
Just after Helen returned to the Permian, Nick realised that the timeline had changed while he was there. The Anomaly then closed before Nick could go back through into the Permian to try and undo the change, and the team then returned to the Anomaly Research Centre.
When the now-fully grown Smilodon which Valerie Irwin had raised began stalking the nearby Blue Sky Park, and ate a guest and the park manager, the Anomaly Research Centre team investigated, and tried to capture the creature when they discovered from photos what it was. Cutter eventually discovered that Valerie was the one harbouring the Smilodon, and Valerie set the creature on him at her house. The Smilodon killed Valerie while attacking Cutter, and the creature was then captured by the ARC.