The Sign of Four (Kobo eBook)
This time the great detective got the task much harder — at least so it seemed to Watson. But for Holmes this is another simple problem to solve. A young lady, Miss Morstan, comes to asks for help: her father disappeared ten years ago, she has been receiving a pearl every year for six years and that day a letter proposing to meet and talk about the injustice came. Holmes and Watson are going to help her to solve the mystery of the 'Sign of the Four'.