The sign of the four

Several years have passed since "a study in scarlet". John Watson wrote the story of their adventure, thinking that Sherlock would be pleased, but the genius criticizes : there is useless romance, not only facts.

But Watson is mainly worried and upset about his companion drug habit : cocaine or morphine are supposed to stimulate Sherlock's bored mind, but how can he damage his extraordinary capacities ? 
Fortunately, a new case arrives with a charming visitor : Mary Morstan

A study in scarlet

Adaptations made in the show from the original story.

London, around 1880.

John H Watson (narrator) was graduated as Doctor of Medicine in 1878, and became an army surgeon. Wounded in Afghanistan, he is back to London, with few resources and no kin nor friend.