The speaker sets out at midnight on a strange errand: carrying a tin box of spice to the dead. The image feels half ritual, half folk tale. Spice suggests an offering, something to give the dead a little flavor or comfort, and the tin box makes the whole thing seem small, homemade, and a bit lonely. The dead are described as "trouble" to the speaker, so this isn't a peaceful act of remembrance. It sounds more like a duty the speaker can't shake, or a guilt that keeps coming back.
The ending is bleak and a little wry. The speaker "gets nothing and sees little," as if the search is pointless. Comparing it to "a history of twelve at night" suggests that the past itself is dark and hard to see, a record of hours where little can be made out. The mood is eerie, quiet, and uneasy, with a dry humor underneath. The hunt may be for answers, and midnight gives none.