Three years after the blackout. The children are entering the second phase of their development. Susannah notices changes in their behaviour and makes a terrifying discovery. Her worst fears are realised when a forgotten mother emerges.

Whilst investigating Amrita's disappearance, Paul's own attachment to Nathan is challenged. Susannah tries to understand the cause of the children's violent instincts. The children now see Susannah as a threat and use their powers to neutralise her.

With Susannah ostracised, the children's hold on Midwich strengthens. When Paul awakens to the children's true nature, he pleads with Susannah to try to forge a truce with them. Meanwhile Zoe and Sam are galvanised into action by another miracle.