Victoria Bennett leaned back from her easel, squinting at the canvas that stood in her downtown New York studio. It was a serene landscape, a picturesque meadow with flowers, yet something seemed missing. Her eyes trailed to an empty space on her palette where a certain shade of black used to be—a black so dark it seemed to absorb light. It was a color she’d mixed herself and could never replicate: Obsidian Black, she called it.She had only used it once, for a single painting that she had sold to a mysterious collector. He had insisted on anonymity, communicating only through a series of encrypted emails. "I need to feel the darkness that I see in your work," he had written. After selling that piece, she had experienced a wave of success she had never dreamed of: interviews, exhibitions, skyrocketing sales. And yet, somehow, she felt empty without Obsidian Black.A chime from her laptop announced a new email. The subject read: "The Return of Your Darkness." Intrigued and slightly unnerved, she clicked on it. The message was from the same anonymous collector."Dear Victoria, I would like to commission a new work. The world must witness the shadow that only you can create. I have sent you a package to aid in this...