J.K. Rowling is the Creatrix of the Potterverse and all who live therein. I am nothing to her, neither can I claim the Miracle of this creation.
It was mid-August and clear to everyone that the Final Battle, as it was coming to be called, was approaching fast. Muggle relatives of Voldemort's enemies had been killed already. Albus Dumbledore had procured a block of flats and made them Unplottable, to house the Muggle relations of Order members.
Lupin and Tonks got the easy assignment: See Hermione Granger's parents and persuade them to go to the Unplottable flats. Their lives were in danger.
Severus and Minerva drew the Dursleys.
They were suitably dressed for the Muggle world, for a change. Potter insisted that his aunt and uncle wouldn't even open the door if they suspected anyone from the Wizarding World, so he and Granger had been the final arbitors of Severus's and Minerva's clothes.
Conservative suit and tie for Severus, a sensible tween suit and walking shoes for Minerva. They carried pamphlets which resembled tracts. Dumbledore thought it would be a good idea to imitate a religious sect to allay suspicion of neighbours on the street.
Minerva rang the bell, then stepped back to stand beside Severus. "Remember what Mr. Potter told us about them."
Severus grunted. It had only been a few minutes ago, he was quite sure he remembered. Severus didn't think much of the Dursleys to begin with. Muggles, related to Lily Evans Potter. And, they were biased against wizards. Potter had mentioned that little point maliciously.
"You talk to the uncle and I will speak to the aunt. Either way, it is the boy we must convince."
The door opened a crack and a thick-faced young man peered out. "We don't want any," he said, glaring at the pamphlets.
Severus braced his foot against the door and stared into the boy's eyes. "Repent, Dudley Dursley, your end is near."
The boy staggered back and they were inside.
"How did you know my name? Who are you?" He was flexing his muscles, toned but overlaid with fat.
Severus thrust the pamphlet into his sausagelike fingers. "The Dark Lord cometh with his Dementors to steal your soul."
The drawing on the pamphlet's cover was of a snake-like man surrounded by his decaying, hooded servants. Potter's worthless cousin trembled and the tract slipped through his fingers. He backed up into a hutch and spilled some dried flowers to the floor. "Mum! Mother! Some wizard's here to see you!"
At least Minerva was amused. She rubbed an elegant hand under her nose, effectively hiding the quirking of her mouth. In seconds, a huge man burst out of the lounge while a scrawney, horse-like woman fluttered in from the kitchen. Severus was glad Lily hadn't looked like that. At least Hogwarts got the pretty sister.
Minerva made no move to speak to either one of them. Severus advanced, holding the woman's eyes. "He is coming for you, Petunia Dursley. He will squash you like the Muggle pest you are."
The fat man's face had gone completely purple, but it was the woman who spoke.
"Y-you, you cannot touch us! I'll... I'll send for Albus Dumbledore! We have wards! We have protection!"
"In fact, it was Albus Dumbledore who sent us. Have you read about the Muggle deaths in Birmingham and Norwich? What about the ones in Redditch? Perhaps you have read about the ones in York, or have seen them on your Muggle news?"
The woman nodded. Her eyes had grown very large. Severus revised his opinion of her, she looked more like a Thestral than a horse. "My Dudley was attacked by Dementors, two years ago, there in the alley."
"Your nephew was attacked by Dementors. Your son had the misfortune to be there. The next time, your son will be the target. And he can summon no Patronus to protect himself."
"What can we do?"
"Flee. Leave this place."
"Where will we go? I have a duty to my poor sister's child. We have to be here for him every summer, or he'll have no protection!"
The man muttered something that Severus agreed with. But it wasn't his business to agree. "I understand your duty to Lily's child. A new home has been prepared for you, one that is more difficult to find. Your time grows short. Accept our offer and live, or take your chances. Which will it be?"
The man was muttering again. Severus ignored him. Potter was valuable to the mission. His blood protection had to be in place.
The woman threw her head back, and for just a second, Severus saw Lily, proudly defying James Potter, or anyone else who dared to challenge her. The moment flew, leaving the Muggle Thestral staring down her boney nose. "We live."
Severus and Minerva sent as many of the Dursleys' most prized possessions to their new Unplottable flat as possible, then whisked them away from Little Whinging.
"What about my job? My company?" the man finally blustered.
"Oh, Vernon, shut up. What good is your company if you die?"
"Sell it," said Minerva, speaking at last. "We can arrange an agent for you."
"Or, not." Severus grinned evilly. "They can attack you anywhere they find you."
"Do you know Harry?" the fat boy asked, finally finding his nerve again.
Severus gave him a glare. "I teach him."
The boy backed up. "I thought Professor Smith was bad!"
Severus smirked. He would like to see any Muggle professor named Smith put such fear into the hearts of students.
Minerva couldn't stop laughing once they returned to Grimmauld Place. "You should have seen the look on that boy's face when Severus told him that his end was near!"
"Wish I could have been there," Potter smiled.
"It was genius to suggest an evangelising campaign. Severus put the fear of He-Who-Must-Not-Be-Named right into them! He was full of hellfire and brimstone!"
"Is that what you call it?" Tonks snickered.
"If you ever decide to give up teaching," Professor Dumbledore smiled, "You could found a church."
Severus scowled. "I saved three souls today. I've done my part."