A Grave Tree (Derivatives of Displacement) (Volume 3)

To know, to will, to dare, to keep silent…

Abbey’s parents are still missing, possibly trapped in a parallel universe, and the adults around her won't give her any answers. So when she and Caleb once again travel to a possible future—one in which Coventry City is very much not as it should be—it’s up to them, and their neighbour Mark, to try to find her parents and set things right.

But it won’t be that easy. Abbey and Caleb become separated, the stones themselves seem to be breaking down, Mark encounters odd ghosts and his half-sister Sandy beneath the Granton Dam, Ian and Sylvain continue to lead them astray, and a powerful witch named Quinta is reshaping the futures to mysterious ends.

To save the future—or at least get everyone home—science-minded Abbey may have to perform magic. And to do so, she will have to believe…