Fighter features Aguilera wearing a black velvet kimono, with a pale complexion, and long black hair, resembling that of someone who follows gothic fashion. Three pins are lodged in her back, making her hunch. Initially, she is trapped in a glass box, and her kimono is billowing like a balloon. Three gothic ballerinas eat fruit and then collapse. Aguilera then breaks free from the box by pounding on it until it breaks.
Aguilera tosses aside her kimono after furiously removing the pins on her back and throwing them away. A tattered, white, moth-covered dress is revealed, symbolising her metaphoric evolution from a larva to a pupa. In addition, her hair becomes white, and moths fly on to her. Near the end, Aguilera wears an Elvira-type spider dress, again proclaiming that she is a fighter. At the very end of the video, she kicks the TV camera.