In 1849 young Franklin Blake returns to England from Italy to give sweetheart Rachel Verinder the moonstone, a diamond left to her by her late uncle, though the Verinders' butler Gabriel Betteredge tells him he believes it was obtained through murder. At Rachel's birthday party Franklin is annoyed that his cousin Godfrey Ablewhite vies with him for Rachel's affection but when a group of Indian musicians arrive another guest, Eastern expert Mr Murthwaite, tells Rachel they are in fact guardians of the moonstone seeking it return to its temple in India. Next morning the stone has gone and a year later has not been recovered with Rachel now refusing to see Franklin. Written by don @ minifie-1

A year after the police have failed to locate the stone and with the Indians given an alibi Franklin recalls the retired Sergeant Cuff, who took part in the original investigation to reopen the case. Cuff had previously recognized house-maid Rosanna Spearman as a convicted thief and aired his suspicion that she had helped Rachel to steal and sell the jewel to pay off Rachel's debts but the case was halted when Rachel suddenly went off to London and Rosanna disappeared, believed to have died in the local quicksands. . Written by don @ minifie-1

Rachel's cousin Drusilla Clack arrives and tells Cuff and Franklin that both Godfrey Ablewhite and suspected jewel fence Septimus Luker have been attacked and left bound though Godfrey denies any involvement. Rachel claims she knows who stole the moonstone but keeps silent as her mother's death overtakes events. She also turns down Godfrey's marriage proposal whilst Cuff and Franklin discover the contents of a letter from Rosanna to her friend Limping Lucy. Written by don @ minifie-1

Franklin reads Rosanna's letter which takes him to the quicksands and the presumed hiding place of the moonstone but there is no jewel, only Franklin's night-gown which Rosanna, secretly in love with him and believing he was the thief, hid to protect him. Then, knowing he would not return her affection, she killed herself. Later, feeling guilt for Rosanna's death, he learns from his lawyer Mr Bruff his belief that Rosanna convinced Rachel that Franklin was the thief and he pleads his innocence, being shocked when she tells him she saw him steal the moonstone. Written by don @ minifie-1

Franklin learns that Dr Candy, the Verinders' physician, gave him laudanum as a sleeping draught on the night of the theft but Candy's successor Dr Jennings tells him it was more likely to have induced sleep-walking and suggests he take another dose to repeat his actions of the night. Under influence of the drug he is seen to have unconsciously taken the stone and recalls giving it to somebody else for safe keeping. A trip to London with Sergeant Cuff to visit Septimus Luker will expose the real thief, to whom Franklin gave the moonstone, reuniting Franklin with Rachel, before the moonstone is restored to its original home. Written by don @ minifie-1