A thousand years ago, many millions of whales dominated the sea, with their ancient behaviours vital to the well-being of the oceans. These marine mammals are the ambassadors between one world and another, land and sea, their close communities only now being truly researched and understood. They are still a keystone species in our fragile ecosystem today, with crucial impact on our seas and the life contained within them. But whaling decimated their numbers over the last 150 years, in particular the whaling industry run by the KGB during the Cold War. In a basement in Odessa, top-secret Soviet whaling reports record the unimaginable number of whales killed. This film tells how surviving members of the Soviet leadership, and original Soviet whalers, uncover these secret records, allowing us to understand the magnitude of historical whale populations and the shocking impact of commercial whaling.