Kellie O'Rourke needs answers. Who was her father and where did her half-sister Alice come from? After the death of their mother, Kellie discovers letters which could explain everything. Alice is mixing with the wrong crowd and out of her depth. When the thugs come for her, they find Kellie instead. Now Kellie is involved in something far more dire than her half-sister's identity. MI5 analyst Eva Merriman is part of a team investigating a string of deaths across the country. The toxins involved have raised the threat level to critical, and now the security services are taking a keen interest. Meanwhile, a sinister organisation continues its testing program of death. Their intended target and location is breath-taking in its audacity, with the potential to bring the country to its knees. As the deaths begin to mount, can Kellie, and unbeknown to her, Eva, stop a madman and his organisation before it's too late?