Severus Snape cast a final, satisfied glance over the rack of phials containing the pale pink stomach soothing potion he'd just produced at Poppy Pomfrey's last-minute request, then emerged from his personal lab with the intention of claiming a half hour on the couch, with the Prophet and a cup of tea, before contemplating the horrors of tonight's Feast, where the majority of the students would be rowdy and overexcited at the prospect of returning home tomorrow for the Yuletide break.

He'd just turned to the Quidditch pages at the back of the paper when the Floo flared, and the wrinkled face of the Headmaster appeared in the grate. Not for the first time Severus wished he'd taken notice of the line in his contract stating that the Headmaster had access to his quarters at all times.

"Ah, Severus. I'm so glad you're not busy," the old wizard said. "Could you come up to my office now please – I have a favour to ask of you."

Snape sighed as his thirty minutes of downtime disappeared, but gathering up his outer robes he shrugged them on and obeyed the command, deciding to walk rather than use the Floo just to show the headmaster what he thought of the summons.

The castle ghosts were out in force, more of them weaving in and out of the walls than he'd seen since Halloween, as Severus stalked along the garlanded corridors of Hogwarts to all too quickly reach the statue guarding the staircase leading to Albus' office. He grimaced at the fake snowflakes falling on his head as he spat out the password. Mint humbug. Bah humbug more like.

"Severus! Come on in, my boy!" Dumbledore's voice sounded cheerfully as Snape raised his hand to knock on the closed door, so he pushed it open instead. "Please, sit down. Would you like a seasonal treat?"

Snape regarded the tray of chocolate…... reindeer droppings… and ice mice, and the jar of sherbet frosted liquorice wands with the contempt he felt they deserved. No reply necessary.

"No? Oh well, all the more for me," the Headmaster smiled. "I'll cut straight to the chase shall I? I need you to visit a Muggle raised child to investigate a major incident of accidental magic that occurred about an hour ago."

Snape stared at him in disbelief. You what!

"As Slytherin Head of House, you may not be aware that the Ministry leaves it to the Hogwarts headmaster to keep an eye on developments with Muggle born or raised children under twelve who are down to be educated here." Dumbledore indicated an array of silver instruments lining a shelf, most of which appeared to be doing nothing. "A home visit or two normally sorts things out. After all, most Muggles only see what they expect to, so magic mostly passes unnoticed. I usually send Charity, but since you know this family I think you are the better choice today."

Snape continued to stare as the penny dropped. Potter? It has to be Lily's boy! I 'm fairly sure I heard he was placed with Petunia, and I don't know of any other Muggle raised child.

"I require you to investigate the causes and fix the results of an episode of accidental magic performed by Harry Potter at Number Four Privet Drive, Little Whinging." The headmaster spoke slowly and clearly, confirming Snape's suspicions, while the steely glint in Albus' eyes told him that refusal was not an option. That didn't stop Snape from glaring as the Headmaster passed him an engraved button and smilingly explained, "This will give you access through the wards on foot. You'd be best to Floo to Arabella Figg's house today until you find somewhere secluded to Apparate to and from. Oh, and Severus, don't forget you need to dress as a Muggle. Here let me help."

Severus snarled as he reached the door, nearly tripping over the toes of the winklepicker shoes Albus had given him to go with plum coloured velvet trousers and a brightly patterned knitted sweater. He smirked as he transformed the footwear back into his customary, comfortable boots as he rode down the staircase, and the colours to black as he reached the corridors. It was a running joke between them that pureblood Albus would pretend to know more about Muggle customs than the partially Muggle raised Severus.