The narrator is alone in a house with a lockless door when he hears an unexpected knock. He immediately blows out his candle in terror and tiptoes to the door, silently praying that no one will come in. Upon hearing another knock on the door, the narrator hastily jumps out the window to safety and shouts “Come in!” to whoever (or whatever) was knocking.
This poem is made up of five stanzas of four lines each. Each line is very short and written in the dance-like “tumbling” meter of two feet per line with one to three syllables per foot.
The poem is based on an autobiographical event that occurred early in Frost’s career. Throughout his childhood, Frost was extremely afraid of the dark, to the point where he slept on a bed in his mother’s room through his high school years. In 1895, Frost was staying alone in a cottage on Ossipee Mountain when he heard a knock on the old, lockless door. Frost was too terrified to answer the door but jumped through a window in the back and then called “Come in!” from the outside. The next morning, Frost returned to the cottage and found one of his neighbors in a drunken slumber on the floor.
In the poem, Frost takes the comic event and creates a more ominous force outside the lockless door. He uses the term “whatever” instead of “whoever” in order to express the knock’s unknown and potentially threatening origin, as well as the abstract nature of the narrator’s own fear. Frost also highlights the narrator’s terror by using short, stilted lines and placing the stress on the final syllable of each statement.
In the final stanza, Frost gently mocks the terrified narrator (and himself) by pointing out that a simple knock is enough to make the narrator completely leave his home for the “safety” of the New England winter. Frost also suggests that the narrator is losing an opportunity to save himself from isolation: this is the first knock on the door for “many years” and possibly the first chance that the narrator has had to meet another person for an equally long amount of time. Rather than communicating with another person in his “cage,” however, the narrator chooses to abandon it completely.
Significantly, the narrator still invites the person outside to “come in,” but only after he has established a detached position outside the house. He is willing to offer hospitality, but cannot bring himself to offer the hospitality on a personal level: even if the person does enter the house, the narrator will not be there to welcome him. Yet, in his effort to escape the person at his door, the narrator inadvertently escapes his own enforced isolation. Since he cannot reenter his house (not knowing who is in there), the narrator is suddenly forced to interact with the rest of the world and finally “alter with age,” adapting to others than only himself.