Caesar's Wife
When the news comes that Bellatrix has escaped from Azkaban, Narcissa is not joyful.
Her sister will only cause trouble, and trouble is the one thing Narcissa does not want. She and Lucius are above reproach. She has worked hard to make it so, to minimize the public belief that Lucius is in any way affiliated with the Dark Lord or the Death Eaters.
Lucius will be Minister of Magic someday, regardless of what happens between Voldemort and Dumbledore. She has worked hard to ensure a base of support for him separate from the Death Eaters, amongst those wizards too scared or soft-hearted to follow the Dark Lord, but too disgusted by Dumbledore's Muggle-loving ways. Dinner parties and hunts, Yule balls and Easter breakfasts -- Narcissa is the consummate politician's wife, and she has molded Lucius into the consummate politician, a middle way between madness and stupidity.
After all, what is the point of marrying a Black if you don't take advantage of what she has to offer, and Blacks have been ruling wizarding Britain from behind the scenes for a thousand years.
She tries not to think of Andromeda, married to her bran-faced Muggleborn, disowned and disinherited. If rumor is to be trusted, Andromeda is happy, and her daughter has joined with Dumbledore and those insufferable Weasleys, preparing to fight against the Dark Lord.
Andromeda was always the happy one.
Bellatrix was the cleverest, but she is mad now, even more dangerous than before, and not to be trusted.
Madness runs in the Black bloodline the way power does; one has only to look at Sirius and Bellatrix, two sides of the same coin, devoting themselves to ideals and principles, serving masters other than themselves, though to completely different ends.
Narcissa has always been the practical one. She is ruthless behind her innocuous smile and expensive pearls. She knows what is owed her family names, both Black and Malfoy, and she has drilled her son in that knowledge. Sadly, Draco shows no sign yet of having any of her skill or subtlety in gathering power and influence. She hopes he'll grow out of his boyish need for brute force and vulgar displays, but fears that he is too much his father's son, or perhaps it is that men are rarely gifted with the art of subtlety, and have to learn it through life's hard lessons.
She would spare him hardship, which is her other, secret reason for keeping her hands clean. She loves her son, painfully, and wishes to keep him close and protect him from what she knows is coming.
When Lucius is sent to prison, she sees all her dreams begin to crumble. It is a major setback, even though she knows he will not be there long. She adjusts her plans accordingly.
She, after all, is still above reproach.
A Malfoy will become Minister, she thinks, as she smoothes back her hair and pastes a pained yet hopeful smile on her face to meet with her solicitor. And if it is she instead of Lucius, so much the better.