The strange case of Mikhail Khodorkovsky — once believed to be the wealthiest man in Russia — who rocketed to prosperity and prominence in the 1990s, served a decade in prison, and became an unlikely martyr for the anti-Putin movement.

Mikhail Khodorkovsky is back to challenge Putin’s grip on power. Once Russia’s richest man and head of energy giant Yukos, he spent a decade in jail after challenging the Kremlin. His takedown sent a strong signal to Russia’s powerful tycoons not to meddle in politics. For the first time after his release, he talks about his time behind bars and his vision for a new Russia. He relaunched the Open Russia Movement to strengthen democracy in Russia - a move towards presidency?

Khodorkovsky, the richest Russian, challenges President Putin. A fight of the titans begins. Putin warns him. But Khodorkovsky comes back to Russia knowing that he will be imprisoned, once he returns. When I heard about it, I asked myself: why didn't he stay in exile with a couple of billions? Why did he do that? A personal journey to Khodorkovsky.