Lady Emma Windsor awoke to the sound of her maid, Jenkins, frantically knocking on her bedroom door. "Milady, it's gone! The Windsor Diamond Necklace has vanished!"

Lady Emma rushed downstairs to the grand ballroom, where she found Jenkins in tears. The necklace, a family heirloom passed down through generations, was nowhere to be found.

Detective Jameson was called to investigate. He questioned the staff and guests who had attended the previous night's ball. Suspicion fell on Lady Emma's nephew, James, who had been struggling financially.

As Detective Jameson dug deeper, he discovered a cryptic letter opener on the floor near the display case. The opener bore an intricate design, similar to the Windsor family crest.

Lady Emma's personal assistant, Ms. Thompson, seemed evasive during questioning. Meanwhile, the chef, Monsieur LeFleur, reported seeing a suspicious figure lurking around the estate's gardens.

As the investigation continued, Detective Jameson uncovered a web of secrets and lies within the Windsor household. But could he solve the mystery before the necklace was lost forever?