Who would want to kill a time-travelling librarian? Time-travelling police detective Erik Midgard thought he had changed his fate. But now he is burdened with new knowledge that suggests the future is more flexible than he thought. He might not have escaped his predicted destiny after all. To make things worse, he has another murder to solve. At the solar system's greatest university on the moon, a group of historians and their students are using time travel to recover the great lost libraries of ancient civilisations. Travelling back to times before these libraries were destroyed, they are secretly recording the contents of all the books and bringing the data safely back to the present. They have saved the entire collections of the libraries of Alexandria, Ctesiphon, Nalanda, the Serapeum, the House of Wisdom in Baghdad and the Mayan libraries of the Yucatan and have many more still to rescue. They have already learnt countless new facts about the civilisations that created these libraries and the project has so far been an unqualified success. But when the professor who founded the project is found dead, it very quickly becomes clear to Erik and his partner Mirabi that something else is going on. Newly promoted after their success at the Time Traveller's Ball, this should be a straightforward murder investigation. But the project's staff, students and security guards are all hiding more secrets than the libraries they have rescued contain, and at least one of them is prepared to kill to protect them. But as they search for answers, Erik starts to suspect that one of the secrets might just be a way to solve the unsolvable. And if it is, could it also be a way for him to save himself?