The myth, as it's usually told
Cassandra, a princess of Troy, was offered the gift of prophecy by Apollo. She accepted the gift and refused the god, so he cursed it: she would always see the truth, and no one would ever believe her. She warned Troy about the wooden horse and was called mad. Taken to Mycenae as Agamemnon's prize, she foresaw her own murder and walked through the palace doors anyway.
What the song hears
Not the warning. The exhaustion. By the time she sings, she has already watched you die.
