The mood of “Young Goodman Brown” is initially foreboding, since it’s clear from the start that Goodman Brown’s venture into the forest will not end well. And indeed, as Goodman Brown suppresses his anxiety and continues deeper into the forest, things keep getting worse and worse for him, which ratchets up the narrative tension. Here's an example of that foreboding mood, a passage that conveys the sense of nebulous danger that Goodman Brown feels as he begins his journey:
He had taken a dreary road, darkened by all the gloomiest trees of the forest, which barely stood aside to let the narrow path creep through, and closed immediately behind. It was all as lonely as could be; and there is this peculiarity in such a solitude, that the traveller knows not who may be concealed by the innumerable trunks and the thick boughs overhead; so that, with lonely footsteps, he may yet be passing through an unseen multitude.
After the story’s climax, in which Goodman Brown thinks he sees Faith consorting with the devil and therefore loses his religious faith and faith in humankind, the mood of the story turns bleak and dismal. While Goodman Brown lives a long life after his night in the forest, he’s never happy again; the story ends with words like “distrustful,” “desperate,” “drowned,” and “gloom.” This leaves the reader with a tragic sense of encompassing despair.