The cold winter air bit sharply at Clara's cheeks as she stepped out of the black armored SUV and onto the icy sidewalk of downtown Zurich. The snow had finally stopped falling, leaving the city quiet, bright, and covered in a thick layer of white.

Directly in front of her stood the massive, grand building of Zurich International Bank. Its giant stone pillars rose high into the clear morning sky, looking like an ancient castle built to guard the greatest riches in the world. Heavy brass doors stood at the top of a wide marble staircase, guarded by armed security officers in dark blue suits.

Clara pulled her black cashmere...