The last soldier's last stand.

Alone. Leda is the last living member of the brigade, the sole defender of her world. War took everyone she knew, leaving her in the company of memories and ghosts. Or is it madness? The siren blares. The enemy is coming. Or is it? The approaching vessel isn’t a friendly design, but it answers with the correct code. Leda must figure out whether the arrival is reinforcements or the final assault. In an aging flyer, she ventures out to meet her world’s fate, the last stand.

Space opera. Short story.