The Doors of Eden by Adrian Tchaikovsky

Lee’s best friend went missing on Bodmin Moor, four years ago. She and Mal were chasing rumours of monsters when they found something all too real. Now Mal is back, but where has she been, and who is she working for?

When government physicist Kay Amal Khan is attacked, the security services investigate. This leads MI5’s Julian Sabreur deep into terrifying new territory, where he clashes with mysterious agents of an unknown power ­who may or may not be human. And Julian’s only clue is some grainy footage ­– showing a woman who supposedly died on Bodmin Moor.

Khan’s extradimensional research was purely theoretical, until she found cracks between our world and countless others. Parallel Earths where monsters live. These cracks are getting wider every day, so who knows what might creep through? Or what will happen when those walls finally come crashing down…