Equations of life

Samuil Petrovitch is a survivor. He survived the nuclear fallout in St. Petersburg and hid in the London Metrozone - the last city in England. He's lived this long because he's a man of rules and logic. For example: GETTING INVOLVED = A BAD IDEA. But when he stumbles into a kidnapping in progress, he acts without even thinking. Before he can stop himself, he's saved the daughter of the most dangerous man in London. And clearly: SAVING THE GIRL = GETTING INVOLVED. Now, the equation of Petrovitch's life is looking increasingly complex: RUSSIAN MOBSTERS + YAKUZA + SOMETHING CALLED THE NEW MACHINE JIHAD = ONE DEAD PETROVITCH. But Petrovitch has a plan - he always has a plan - he's just not sure it's a good one.