Permafrost

2080: at a remote site on the edge of the Arctic Circle, a group of scientists, engineers and physicians gather to gamble humanity’s future on one last-ditch experiment. Their goal: to make a tiny alteration to the past, averting a global catastrophe while at the same time leaving recorded history intact.

To make the experiment work, they just need one last recruit: an ageing schoolteacher whose late mother was the foremost expert on the mathematics of paradox.

2028: a young woman goes into surgery for routine brain surgery. In the days following her operation, she begins to hear another voice in her head . . . an unwanted presence which seems to have a will, and a purpose, all of its own - one that will disrupt her life entirely. The only choice left to her is a simple one. Does she resist . . . or become a collaborator?