Rachel's eighteenth birthday is celebrated with a large party. She wears the Moonstone on her dress that evening for all to see, including some Indian jugglers who have come to entertain. Outside her Yorkshire country house watch the Hindu priests who have waited for many years to reclaim their ancient talisman, looted from the holy city of Somnauth. Later that night, the diamond is stolen from Rachel's bedroom, and a period of turmoil, unhappiness, misunderstandings and ill-luck ensues. The bemused butler, the love-stricken housemaid, the enigmatic detective Sergeant Cuff, the drug-addicted scientist-each speculate on the mystery, but in mid-Victorian England no one is what they seem, and nothing can be taken for granted.