sentences:  After repairing Zanak's engines, which were damaged when the planet materialised in the same place as the TARDIS, the Captain plans to take Zanak to Earth.The Doctor finds the true menace controlling the Captain is the ancient tyrant Queen Xanxia, disguised as the Captain's nurse, who uses the resources mined from planets in an attempt to gain immortality.Her physical body sits between Time Dams, devices that hold back the ravages of time as she is old and near death, and a younger version of her is projected via a sort of solid 3D device.