The Valley of Fear by Sir Arthur Conan Doyle

Sherlock Holmes receives a cryptic message from one of his informants, on deciphering this clandestine message, Holmes and Watson discover that someone named John Douglas is in great danger. Inspector MacDonald comes calling on Holmes with the news of a man called John Douglas, who has been mysteriously and brutally killed in Sussex.

John Douglas has been killed in his own home, surrounded by a moat, wide but only two or three feet deep.  The house has a drawbridge which is drawn up every night. John was shot through the face by a sawed shotgun, so whoever intended to murder him was not looking to keep things quiet, the police identify his body by a tattoo of a triangle inside a circle on his forearm, another perplexing mystery to the murder is that John's wedding ring is missing, the wedding ring was under the nugget ring which was found intact, why would someone take only the wedding ring? other residents of the house tell the police that John was a brave man but always had seemed troubled by some unknown danger. Holmes tries to use his deductions to solve this case of murder, secret societies and master criminals.

The Hound of the Baskervilles by Sir Arthur Conan Doyle

Many years ago Hugo Baskerville had committed an atrocious and deplorable sin for which he was aptly punished but the punishment did not stop there, a terrible curse was put on the Baskervilles which has plagued them for generations. A Hell hound, a beast that is so frightful that the mere act of looking at it causes unimaginable horror to its victims. Legend says that the beast is a bloodhound which can track its victim from one end of the moor to another, it is as big as a lion and as vicious as a  pack of wolves, it has great big flaming eyes which can conjure the fires from hell itself.

A descendant of the Baskervilles, the amiable and benevolent Sir Charles Baskerville,  takes up his abode at the Baskerville hall. He acts as a benefactor to the village people and makes a lot of friends in the community  but always in the back of his mind are the moors and that hell hound. One fateful night Sir Charles ventures in the desolate moor and is found the next day, dead. His face contorted in a ghastly expression and his footprints on the moor suggest that he had been running from something, Nearby, Mortimer(a friend of Charles) discovers footprints of a gigantic hound!

After Sir Charles death, the whole estate is bequeathed to Sir Henry Baskerville, the last living descendant of the Baskervilles. The lone Baskerville decides to take up his residence in the same Baskerville hall and in the same moor. Mortimer has no choice but to approach Holmes for advice and protection. Holmes and Watson vow to protect their client from this curse and end this superstition, but as Watson and Holmes will soon find out legends can sometimes come true.

The Sign of Four by Arthur Conan Doyle

Sherlock Holmes is given a tricky little problem. Mary Morstan is getting pearls in her mail every year for six years. she does not know who sends it or why they send it. Miss Morstan has now received a letter which urges her to meet with the sender that night. The anonymous sender permits her to bring two friends as long as they are not police. now take a guess who those two friends might be? Holmes and Watson travel with the Mary Morstan to meet the sender.

The sender is Mr Sholto whose father Major Sholto had mysteriously come to acquire a treasure and that Mary Morstan's father had an equal share to that treasure. So, Mary whose father had passed away should be bequeathed with half of the treasure. The only problem is that the Major Sholto had hidden the treasure in his Norwood home and his sudden demise left Mr Sholto and his twin brother perturbed as they did not know the location of the treasure.

After searching for 6 years they have finally found it. Now Mr Sholto wants to take Mary Morstan with her to his father's Norwood home where they will divide the treasure. So, the four of them Mary Morstan, Mr Sholto, Homles and Watson start off to get the treasure but instead they get a murder.

Review:

A Classic of the genre or a horrible racist mistake by Sir Arthur Conan Doyle?

A Study in Scarlet by Sir Arthur Conan Doyle

  Plot: Dr. Watson has returned to London from a brutal war in Afghanistan, broke and convalescing from his injuries, Watson needs a place to stay. Soon, Watson meets the eccentric and brilliant Sherlock Holmes with whom he will share his residence at Baker Street. Dr Watson finds out the Holmes is a consulting detective and is a polymath whose skills in deduction are unmatched.

Police Detectives are frequent visitors to the Baker Street resident, where they seek Holmes advise on unusual and tenebrous crimes. On one such faithful day, Holmes gets a letter from the Police about a most perplexing murder. A man was found dead in an abounded house without an injury on his body but there are marks of blood in the room and "RACH" is written in blood on the wall.

Lestrade and Gregson want Holmes to help them in the case where the next victim of the murderer is the Prime suspect.