The Lady of Obsidian

As a Dalek Strike Fleet heads to destroy another defenceless world, the Doctor seeks help from a shadowy guerrilla force. The Time War leaves many casualties in its wake, and inside the Obsidian Nebula the monstrous Unlived are held at bay only by the 'Lady' and her dwindling band of fighters. The War Doctor soon finds himself at the Lady's mercy, and two old friends face new revelations...