An outspoken Russian nuclear scientist disappears while attending an international scientific conference.

Are his theories about nuclear war so shocking that MI6, and perhaps even the CIA, want to dispose of him?

KGB officer Yuri Velikhov investigates the case and learns how tough governments can get when the stakes are high...Welcome to a world where the truth is hidden in files marked Classified!

This electrifying series gives a unique insight into the most intriguing mysteries of modern history.

First read the spine-tingling stories, then the fact-filled case files.

Fact or fiction? You decide.