When he answers the door, the speaker sees nothing. He does not know the raven is the one tapping at the chamber door. In fact, he believes it is a visitor. However, when he opens the door, he sees "darkness there and nothing more." The stanza states:
Presently my soul grew stronger; hesitating then no longer,
“Sir,” said I, “or Madam, truly your forgiveness I implore;
But the fact is I was napping, and so gently you came rapping,
And so faintly you came tapping, tapping at my chamber door,
That I scarce was sure I heard you”—here I opened wide the door;—
Darkness there and nothing more.