After the mysterious disappearance of her father, the beautiful Miss Morstan starts to receive a present each year - a very large, rare and lustrous pearl. Who is her secret benefactor, and why do they want to suddenly meet with her? The spellbinding mystery unfolds as Holmes and Watson are caught up in a cat and mouse chase, pursuing a priceless hoard of Indian treasure and a murderer whose ominous trademark is "the sign of four."
