"Lost Bastion"
by Christine Anderson
aka Lilly Malfoy

Two years after Harry Potter graduates Hogwarts, Voldemort stands at the edge of victory, and Dumbledore's Order of the Phoenix is greatly tested when Dumbledore himself falls to the Death Eaters. But like the Phoenix of their knightly order, they arise from the ashes, Minerva McGonagall steps forward to take his place, and fighting at her side is Severus Snape, a Severus Snape who has stood for the last time amongst Voldemort's forces. Snape/McGonagall.

Chapter 1: Phoenix Tears
Chapter 2: Unlikely Allies
Chapter 3: The Auror's Eye
Chapter 4: From The Ashes
Chapter 5: Prisoners And Prodigals
Chapter 6: Serpent Guardians
Chapter 7: Blue and Black
Chapter 8: The Letter and the Testing