The Adventure of the Speckled Band was written in 1892 and The Moonstone was written in 1868. Both of the stories center around mysterious figures in England. They are both mysteries
In The Adventure of the Speckled Band we have a woman named Helen Stoner who has come to Sherlock Holmes for help. Her relative, Julia, has been killed and her stepfather might be behind it. She is terrified and Holmes agrees to help her. Holmes finds out that her stepfather was a member of the Roylotts of England and the last of the family. He loses his money so he goes to India to try to get it back. He does make some money but he causes more trouble than anything else. He meets Helen's mother, whose husband had died, and marries her. She has quite a sum of money and leaves everything to Roylott. She does leave in her will, a stipulation that if Helen and Julia marry, they will inherit some of the money, also. Julia is going to be married, but she keeps hearing a whistling sound in the middle of the night. She asks Helen if she hears it, but she doesn't. About a week before her wedding she ends up being killed. Holmes agrees to take the case. Helen is going to be married and has moved into Julia's old room. She has started hearing the same sounds Julia heard. Holmes knows that Helen's life is in danger, so he goes to the estate and stays.
In The Moonstone, a man named John Herncastle has gone to India and stolen the jewel that is used to honor a god there. He brings it back to England in the mid 1800's and has left the jewel with the aristocratic family. Lady Verinder was born Julia Herncastle and she has a daughter named Rachael. On Rachael's 18th birthday, she is to get the jewel. The jewel is stolen on the night of her birthday and it is eventually returned to India, where it is placed of the forehead of the god.
In both stories, we see characters from England that have gone to India for some reason. Both characters bring something back to England from India. One is a jewel and the other a deadly snake. We see wealthy English characters trying to keep their fortunes. In The Adventures of the Speckled Band, we see murder and dishonesty and in The Moonstone, we see a theft, but it is made right in the end.