As the speaker's mother holds his hands, she sighs, angrily but without crying any tears. At ten, an ambulance arrives at the house and unloads the corpse of the person being mourned. It is damaged, and has been bandaged by nurses. The speaker reflects that it's been six weeks since he's seen this person. The following morning, the speaker enters the room where the corpse is being kept. Beside it, people have placed candles and flowers. Referring to the dead person as "him," the speaker notices that he is bruised on his temple and that he is pale, lying in a small coffin as if it is his bed. Though injured, he doesn't have any very notable scars, because the car that hit him knocked him down so neatly and abruptly. The box-like coffin is four feet long, the speaker reflects—one foot for every year of the person's life.
Throughout this poem, the speaker has done his best to maintain emotional control in the face of what is clearly an upsetting loss. That contradiction between control and devastation has in part been expressed through form. Even while describing grief, Heaney maintains a steady, unbroken stream of tercets with ten-syllable lines. In this second half of the poem, as the reality of the loved one's death is made increasingly vivid, upsetting, and inescapable, the speaker's control slowly crumbles, dissolving by the final line.
In the poem's fifth stanza, the corpse arrives, making abstraction impossible. The death becomes concrete and physical, and the brutality of the way in which the person died becomes clear. Not only are they bruised and cut, but the absence of worse cuts only further hints at the violence to which he was subjected, proving that he was hit quickly and hard. Meanwhile, the speaker's relationship to the loved one becomes clearer. They appear to be members of the same family or household, and likely siblings, because, while home at his parents' house, the speaker refers to the corpse being kept in "his room." In fact, while no knowledge of Seamus Heaney's life is needed in order to understand the poem, the poem is in fact based on Heaney's autobiographical experiences: while a teenager, Heaney lost his four-year-old brother, who, like the child in the poem, died after being hit by a car.
It's already clear that this is an upsetting death. The community members gathered at the home treat it as an important occasion, the speaker's parents are evidently stunned, and we've learned that the dead person is someone close to the speaker. Furthermore, we've learned that they died in an abrupt, violent manner. But the final line contains the most upsetting information of all: the speaker's dead loved one was only four years old. It's clear that this information is extremely distressing to the speaker, too, because he independently draws a connection between the size and the coffin and his loved one's age, editorializing in a way that is rare for a withdrawn speaker who tends to stick to immediate facts.
Meanwhile, as we learn this singularly sad news, the speaker's carefully kept control falls apart. The established pattern of tercets disappears, replaced by a single-line stanza. That single line is a huge clue that the speaker, who seems outwardly not to be grieving as intensely as his parents, is far more affected than he's letting on directly. The very mode with which he has addressed us so far fades, and the poem's final, one-line stanza gives the impression that the speaker has trailed off, too overcome or pensive to finish the tercet.