Snow fell thick over Moscow, coating the Kremlin rooftops and the neon-lit streets with pale silence. But inside Sergei Volkov’s private fortress, silence was impossible.

The walls trembled with music, with laughter, with the sound of glass breaking. Half-naked women lounged across velvet couches, vodka in hand. Armed guards leaned against the walls, watching everything with dead eyes.

At the center of it all sat Sergei.

Broad-shouldered, with scars clawed across his throat, he was dressed in a tailored black suit but wore it like armor, not fashion. A cigar burned between his fingers. His icy blue eyes scanned the room, but his mind was far from the haze of...