The rising action of a story is the part that comes just after the introduction/exposition and which builds to the climax. In this story, the exposition is contained in Helen Stoner’s narrative which relates the grim events surrounding her sister’s death and the background to the case. The rising action begins just after this, when Helen’s stepfather, the fearsome Dr Roylott unexpectedly appears in Holmes’ room, having tracked Helen there. When Roylott confronts Holmes he instigates the showdown between them. Although we have already gained a lurid impression of Roylott from Helen’s narrative, this sudden fierce appearance by him in person establishes him beyond all doubt as a villain.
It is just after this that Holmes, upon making inquiries, discovers a motive linking Roylott to the murder of Julia: he wants her money. The pace quickens as Holmes and Watson then set out to look over the house where Julia died, and where Holmes’s suspicions about Roylott are confirmed, as he notes the unusual set-up of Julia’s bedroom which effectively functions as a trap. Therefore Holmes and Watson decide to sit up in her room that night, secretly, to see what Roylott will do next. This is the end of the rising action. It is followed by the climax where Roylott is killed by his own deadly pet snake, which he used to kill Julia as she slept.