The moment Emily makes her promise to Lady Eliza, the spirit begins to dissolve

The moment Emily makes her promise to Lady Eliza, the spirit begins to dissolve into a mist, leaving behind a locket that had been around her neck. Emily discovers that the locket contains a hidden compartment with a crucial piece of evidence. This discovery adds a new layer to Lady Eliza's story and provides additional clues that could change the course of her investigation.