Helen Stoner and her twin sister, Julia, lived in Calcutta, with their mother, whose husband was an army officer and had died in a war. They were just two when Mrs. Stoner remarriaged, this time, with a doctor: Dr. Roylotts of Stoke Moran, whose family had been once the richest of England. He went to India because of work, where he was very succesful.
Mrs Stoner had quite a lot of money, which became Dr. Roylott's when they marriaged. However, she died after they were back to England, and Helen and Julia went to live in their stepfather's house, where they didn't have many pleasures. Dr. Roylotts had a very agressive temper and they had to do all the housework.
When a man asked Julia to marry him, some days before, she died, but the reason keeps in mistery.
Some minutes before the death, she told Helen that, in the last days, she was listening a whistle in the middle of the night, then she went to the bedroom and, after this, Helen heard a scream.
She ran to the her sister's room and found her twin sister with a white face, speaking: "Helen, it was the Band! The speckled band!"
Julia died in that night, and Helen now was living alone in that house, only with her stepfather.
Two years passed since Julia's misterious death, and an Helen's old friend asked her to marry him.
She accepted it. However, some repairs started to be maden in the west part of the building, and Helen had to sleep on her sister's old bedroom, where she began listening the same whistle Julia described to her, some years ago.
With fear, she calls Sherlock Holmes and his companion, Watson, to solve more one misterious case and save Helen Stoner from a terrible death.
When she goes to Holme's house, some minutes after she tells him and Watson all the story, her stepfather, Dr. Roylott, apears and order Holmes to stay away from his way and house.
However, at night, the detective and his old friend went to Helen's house, without the stepfather's knowledge, to discovery why did Julia die, and what was putting that fear in Helen's hearth.
They decided that Helen would sleep in another room, without Dr. Roylott's knowledge. Sherlock Holmes and Watson would investigate the case, and they realized that there were a ventilator, connecting Helen and her stepfather's room (because Mrs Stoner told them that, when she was alive, Julia, from her room, could smeel the cigarretes in Dr. Roylott's room) and a bell rope in that, near the lady's bed.
Holmes' first conclusion: the stepfather had killed Julia, and he's planning to do the same with the second daughter. But how? How did he kill her? How did he escape from police's radar, without letting any sign of injury on his first victim? Holmes was sure of a thing: he did that through the ventilator and the rope.
Sherlock Holmes had some guesses, and he would try to prove it.
The two detectives started listenning the whistle described by Mrs Stoner. Holmes got near the wall, used his cane and closed the hole of the ventilator. After some seconds, a high cry could be listened. They ran to Dr. Roylott's room and found him dead, in the ground, with a snake.
Bingo! The case was resolved! The doctor had, like Mrs Stoner said, a collection of indian animals, and this includes snakes, very poisonous snakes, whose bite could kill a person in few seconds. Of course the police wouldn't realize that, the bite's mark was very small, almost impossible to see.
The whistle was just a way to manipulate the snake, to comand her to go where the doctor wants.
Dr. Roylott had a important reason to make that crime: if the girls get married, a big part of his money would pass to them, and he would lose a big fortune. And, like Holmes said: "When the doctor becomes a killer, he's the worst one. He has all the knowledge that's necessary to murder".
The "band", cited by Julia before her death, was the snake, used by Dr. Roylott to save his capital.
And so, more one case was resolved by the skillful detective Sherlock Holmes, and his companion Watson.
