The Time of Sacrifice — Marius Smith

Having just escaped from the events at Kirkstall Abbey near Leeds in 1779, William and the mortally wounded Larissa have been taken from their intended destination and land on the planet Melhandur; a world trapped in the medieval era where technology cannot function. Immediately upon their arrival their time capsule is rendered inoperable. They find out that the people in the various settlements, descendants of groups of humans who have been abducted by aliens in Earth's distant past, are periodically being gathered by an alliance of powerful warlocks and druids to be offered as sacrifices to aliens who come to collect them for an unknown purpose. With the help of the Immortal, it doesn't take them long to realise that Melhandur is a world that the aliens use to breed human beings like livestock.

At the castle estate of Belhamburh they learn that a Temporal Security agent who'd gone missing years earlier had in fact ended up on Melhandur after passing through a space-time portal, which occurred over eighty years ago according to Melhandur's history. The agent had then disappeared again while investigating a centuries-old legend of two wizards who'd been working on a way to protect the people from being taken by the aliens. But the possibility of a space-time portal offers hope that William and Larissa might be able to get back to Earth to be reunited with Luke and Cerah, who were left trapped in 1779. And as they find out more about the origins of the stones that give the warlocks and druids their great power, it becomes clear that they have far reaching implications that go beyond Melhandur.

But the time for the next collection of sacrifices is at hand. The warlocks and druids are planning to attack the local settlements to capture victims for sacrifice, with assistance from the formidable Nordics; warriors decended from Vikings who'd been taken from Earth generations ago. Receiving no help from King Walric, it is left to William, Larissa, the Immortal, and the people of Belhamburh and its neighbouring settlements, to make what alliances they can in preparation for the aliens' arrival, but even within alliances they find treachery and betrayal.