Someone is always watching.  James Fitzpatrick is a high-profile lawyer at a successful City firm. He's married to Bella.

She's beautiful and clever, a teacher at a prestigious private school. They have the perfect lives. But then, one night, James loses a file for a multi-million pound deal he's working on and in desperation contacts the company's IT helpdesk.

A woman named Charlotte answers his call, setting in motion a series of events set to shatter James' and Bella's lives. In the weeks after, James is accused of more mistakes at work, ones he doesn't remember making and can't explain. Meanwhile Bella finds herself the target of vicious rumours at school - and no one seems willing to believe her side of the story.

Everything started with that one phone call. Who is the woman at the other side of the computer screen? And why do Bella and James suddenly find their privileged existence in peril?