A man stands on his porch at dusk, half-dressed, aware that a mother bear and her cubs have come to the edge of the woods. She has sensed him, and he is trying to sense her. But he feels badly equipped. His nose is "grossly unequal" to hers, and his "primate eyes" are no good in the dark, so he has to rely on hearing: the huffing breaths, claws on bark, and the hollow clacking of her teeth, which tells him how big she is.
The mood is tense but also humble. The speaker is close to a wild animal and can barely perceive her. Even the fireflies "illuminate nothing." The ordinary details, like the mosquito and the screen door, make the moment feel real. The ending is quietly startling. In daylight, he finds every rock on the hillside overturned. The bear was searching all along, and the speaker only sees the evidence once she has gone.