The No.1 bestselling book from Mark Edwards and Louise Voss.

A terrifying enigma - with the power to destroy...

Twenty years ago, Kate Maddox was a volunteer at a research centre where scientists hunted for a cure for the common cold virus. That summer, Kate fell in love with a handsome young doctor, Stephen, but her stay ended in his tragic death and Kate fled to a new life in the US.

Now Kate is back in England and on the run with her young son, this time from her vile husband. But a chance encounter sets her on a terrifying path of discovery. What really happened at the Cold Research Unit two decades ago?

Pursued by both her estranged husband and a psychotic killer who is obsessed with his prey, Kate must fight to solve the puzzle of the past - uncovering a sickening betrayal and a truth more horrifying than she could ever have imagined...