Doctor Who: The Kairos Ring

Residing on the threshold of E-Space with the Tharil Laszlo, Romana is on the trail of a terrible enemy. Allies of the enslaved, the duo ride the Time Winds in search of the desperate Sluagh. Meanwhile, on a bloody American Civil War battlefield, young soldier Joshua is haunted by spectres: pale, vicious-looking aliens who prey upon the dead to raise an army of living corpses. With the fabled Kairos Ring they can carve portals into other dimensions - and, by accident, Joshua is blown through one of them. United with Romana and Laszlo against the dreadful Sluagh, Joshua finds himself catapulted into a strange new world of learning. But one secret is waiting to catch up with him...