The Puzzle Woman

A letter with no addressor unexpectedly arrived at Mochizuki’s house, and inside the envelope were a number of pieces from a jigsaw puzzle. He began to assemble it, however when he completed the puzzle it was still unfinished. The puzzle itself depicted a woman wearing a most characteristic anklet. “What… is this?” he asked himself. One by one the puzzle pieces arrived, and Mochizuki would assemble them. Soon he began to sense he was being followed around by the woman from the puzzle. One evening he saw a leg wearing the anklet, and later at night a mysterious woman grabbed him around the neck. Just who is this woman, and what are her intentions towards Mochizuki?