(a) what is the narrator's first impression of the house of usher? (b) why has he come to the house?

In the opening paragraph, the Narrator is describes his arrival on horseback at Roderick Usher's isolated abode one dreary evening. He immediately feels an irrational fear upon viewing the huge, decrepit house. Among the mansion's singular features are windows which resemble eyes and a fissure in the stone zig-zagging its way through the fasade.

We learn that the Narrator and Usher were childhood friends. Recently, the Narrator received a letter from Usher. In the letter, Roderick described a certain "mental disorder" that was plaguing him, and he communicated a desperate desire to see his old companion.