The poem sets a small, strange scene: a palace in ruins, a queen's rule long gone, and peacocks strutting along the broken walls at dusk. The title, "Interregnum," means a gap between reigns, and that idea hangs over everything. The queen's time is described as a "brief flaming," as if her power was a fire that burned hot and quickly went out. What's left is empty grandeur, now taken over by showy birds.
The speaker seems to watch from a distance, without stating a clear feeling. Still, the tone feels uneasy and a little mournful. One peacock calls, and its cry is called "hideous," a harsh word for such a beautiful bird. The "thousand eyes" are probably the eyes on its tail feathers, and they seem to stare at the coming night. The mood is eerie and watchful: power has faded, beauty has turned grotesque, and something unnamed waits in the dark. The poem suggests that glory is temporary and that what replaces it can be strange and unsettling.