A herd of rhinoceros-like creatures, embolotherium, come through a rift at a camp-site. Danny rescues Eve, the young woman Johnson and Wilder have brought from the future and takes her to the site where she saves the day with a device which creates an anomaly, through which the beasts return home. She is taken to the ARC where she is not who she first appears to be.

Sarah and Becker battle giant insects who have come through the rift at Johnson's H.Q. whilst Abby, Connor and Danny pursue Helen Cutter through the anomaly she has created. Her plan is to travel back to Africa in the year four million B.C. in order to stop the evolution of human life. With Connor injured Danny faces her alone but has an unexpected ally to help him save the world. Can he make it back to his own time before the anomaly closes?