The cold night air carried a terrifying silence right after the final scream vanished into the pitch-black void below. Fifty stories up in the sky, the wind continued to howl through the open steel frame of the uncompleted Landmark Tower, blowing thick sheets of freezing rain across the wide concrete floor.

Julian Vance remained flat on his chest against the slick edge of the drop. His muscles screamed in agonizing pain, and blood from his grazed shoulder mixed with the rainwater pooling around his body. Yet his dark eyes never wavered, and his grip on his left hand never loosened for a single fraction of a second.

Down below the...