As Yevgeni Grushko, head of the Criminal Investigation Division of the St Petersburg police, continues his inquiry into two brutal murders in the city, he begins to uncover the most horrific story of his career. A murdered TV journalist was working on a television documentary - an exploration into nuclear waste and possible mass radiation. But there is a missing link - Grushko and his sidekicks, Nikolai and Sasha, search relentlessly for the key.