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?