After his brother's random murder is captured on CCTV, Mark becomes determined to find the killers. Paranoia and fear of intruders haunt Mark, who decides to take full control and install a surveillance system in his own house, so he can monitor the world constantly. His best friend, Tom, is disturbed by what Mark is doing, and persuades him to stop doing it. Mark wants to live his life again, but it isn't long before he forgets about what he's actually looking for and is sucked in to a terrifying world of his own creation. As this world threatens to engulf him, it first throws Mark an ultimatum: continue observing his life, or live it?