Or She Dies - Gregg Hurwitz, Sphere

First, Patrick receives the mysterious DVDs. They show invasive footage of him in the privacy of his own house. Soon, Patrick and his wife Ariana find themselves questioning everything and everyone as their lives unravel. Someone is clearly out to get them. And then, the email arrives: Go Alone Do What We Say Or She Dies A compulsively readable novel about an ordinary couple in a deadly situation, Or She Dies is the must-read thriller of the year.