Soldiers break into a castle after a long siege, expecting victory, and find only death. The bodies lie in "ugly sleep," stripped of dignity yet strangely at peace, while the few survivors seem worse off, their eyes damp with terror and their mouths making sounds the speaker can hear but not understand. The attackers search for an explanation, some sign of a last stand, and find nothing to make sense of what they see.
Then the walls start growing, and the conquerors become the trapped. The final line, "& at last we understood," is left hanging, and the poem never says what exactly they grasp. Given the title, "Trauma," the castle seems to stand for a mind or memory, and the siege for a long struggle to get inside it. The speaker's feelings move from grim determination to confusion, then to helpless fear. The mood is eerie and claustrophobic, and the ending offers no relief, only a quiet, chilling recognition.