An archaeological dig in Sheffield uncovers the remains of a Dalek, buried since the 9th century when the combined armies of the Earth barely succeeded in defeating it. Accidentally revived, the Dalek takes control of Lin, one of the members of the dig team, and uses her to construct a new body for itself. The Doctor finds herself in a race against time to save Lin and prevent the Dalek from summoning an invasion fleet. But the Dalek is not the only old ghost who has appeared: Ryan and Graham must contend with their own past when Grace's son Aaron returns to celebrate the New Year with the family he has long neglected.