It takes five years.
During the war, she was Tracey Davis. Harmless little half-blood Slytherin.
Now, she is a Unspeakable in the Ministry. Croaker plucked her from the grounds of Hogwarts with dirt embedded in her nails and her wand clutched in a bloody fist.
('What does she do?'
'Everything.')
She researches magic that was forgotten when the Romans burned sacred wand groves. The magic weaving through her hands remembers day when magic was born under the stars and in dark caves. Days when kings bent to the will of mages. Tracey's bones remember ancient majesty. She wakes aching in the mornings, her muscles protesting every movement, overused by magic not seen on this earth for centuries.
She crafts spells from old languages learned from well-hidden books which accented an average Hogwarts career.
She gives her colleges battle spells in Norse; Odin's thunder and honor alive in magic.
(She saves those in Arabic for herself, power and passion wrapped in her words and lingering through her magic)
Formal, distant Latin crafts average charms. These they give to the aurors. (she hears Kevin Entwhistle praising one of them. It was too simplistic and harmless for the Unspeakables)
When she is creating for the joy of it, she uses French, delicacy, suitability, precision. She learned it as a child in her mother's Muggle home. These books she keeps in her rooms. She has no wish to share her secrets with even those who work with her.
She takes rite that were held against the building of Hogwarts and learns them. She binds the three essential components together and Croaker sometimes peers nervously into her laboratory, unwilling to interrupt. This magic is ancient, and even the Unspeakables hesitate to handle it.
She is the heart of the Department of Mysteries. She has a different name there, a hood which casts a shadow over her face, words in black ink curled around her wrist. There might have been a prophecy with her name on it in the Hall of Prophecies. It would not be found if anyone bothered to look.
She refuses three positions at Hogwarts. Minerva offers her the History of Magic position when Sloper quits. She refuses, her work is too important. (She writes Ginny, and the position is given to Marietta Edgecomb.) Tracey does not attend her dinner, instead she works in her lab and crafts a rite of love, hate, and family.
She considers writing Ginny again, to tell her what she has learned of Lily Potter. It takes her two weeks to convince herself that Ginny will do what she thinks is right. Ginny would never sacrifice a friend's health to take a burden off herself. (Tracey rarely drinks but the morning after sending that letter she skips work to nurse a hangover.)
She carves runes into the Veil and out spill ten men sentenced to it. She lets them take nine away, but she stands between Sirius Black and the aurors. Ginny comes through her Floo and clings to the man. Hermione is already preparing his case and Tracey says nothing to Harry's tears and thanks. Ginny takes her hand and nods at her. Tracey does not want to attempt to determine why the praise of a Quidditch star makes her heart warm as if they were hiding in a corridor of Hogwarts many years ago. (Ginny invites her to dinner and tells her about Alice and Frank Longbottom. Tracey likes a challenge.)
Four years later Flitwick offers her the Defense position. He sees her passion and does not judge her her love of light and dark and ancient magics. She turns him down, but goes to Hogwarts to do it. She remembers little Flitwick and his safe office during the Lost Year. She tells him to write Ginny, and sends her own letter off before returning home. (Flitwick writes to tell her the position was given to Mandy Brocklehurst.)
Neville proposes with roses of pale pink sparking with yellow magic and Tracey takes them and admires the spells. (They could be improved with several simple tactics, but they were hand-spelled by Neville, and so she says nothing.) She takes his family ring and admires the spellwork on her finger. (It is old, and she wants to peel into the spellwork and dissect it.)
Tracey is asked to show the newest recruit around the Department, and when he stops in her office he asks her why she loves the ancient magics so dearly when there are useful modern magics that can work just as well. He is never afraid to enter her laboratory again.
The day of her wedding, Augusta Longbottom enters her dressing room. It takes Ginny and Daphne to send her back out, and as she storms away Ginny follows. Luna and Neville pry her away, and she returns to Tracey furious. (She tightens the dress to tight, but Tracey smiles at the anger on her behalf.)
Her co-workers appear to think that she will have five babies and live happily ever after. She hides in her laboratory so long they are convinced she isn't even there, and when she goes home they stare blankly at the skinny, tattered woman with ratty hair. (She has found a rite of bone and blood and flesh. This one she will tell to no one.)
Tracey showers and curls into her and Neville's bed. When she wakes there will be food and books and letters. There is a potion bubbling in the Ministry that could run through veins and purge nerves. A letter sits in her office address to Ginny Weasley. Spellwork is piled into a drawer, failed or succeeded too well. Her hands have killed and her skin remembers sticky blood. Now they remember magic and weaving spells.
The little half-blood Slytherin who was not pure enough to be a Death Eater nor in the right House to be a savior is now the Head of the Department of Ministries.