"'First foot!,' shouts Rose. Is there coal on the step?'"

In British tradition a first foot is the first person to come into a house after midnight has struck to welcome the New Year, bringing good luck to the household. In the North East the tradition is that for the best luck the first foot should be a tall, dark stranger carrying a lump or shovelful of coal. In the story, they are expecting Eddie, the eldest son of the family. Rose complains that "he's not a stranger" and the mother replies "at least he's dark so that's half good luck anyway." The irony is that Eddie's arrival brings division to the family.