In the next moment, two astonishing things happened at once. The first of these things happened to Dean's father. The second his hand touched the door handle he seemed to have a revelation of thought, and he clutched his head in his hands, spun around on the doorstep, then started sprinting down the narrow lane they'd just driven up. The second thing that happened shook the whole house; a ball of flaming heat and shrapnel exploded from an upstairs window, followed closely by something which reminded Dean of Catherine wheels he'd seen on fireworks night with his family. As the cartwheeling shape got closer, he realised it was none other than Seamus Finnigan, his clumsy, accident prone best friend.

"SEAMUS FINNIGAN!" The exclamation came from a short but attractive young witch, who was speaking with more danger in her voice than a thousand of Seamus' explosions. She seemed surprised to see the bemused Thomas family; her aged features didn't seem to fit her youthful appearance, giving her the look of someone who was thinking about too many things for her head. Her sandy curls were clumped back in a fat pigtail and she wore a stained apron on her narrow hips, grey-white, with a pattern of orange and green pumpkins.

"Oh, I am so sorry! I'm Seamus' mother, Aislin, call me Ash. You must be Dean, and - Merlin's Beard!" The witch had just spotted Mr Thomas sprinting down the road and reacted much as he had on reaching the shop's door. She clutched her head and span, but instead of charging down the road she whipped out her wand. Dean's mother looked mildly horrified as green sparks flew from the pointed beige stick towards her husband, but simultaneously seemed to have no idea what to do to stop the proceedings, so let the witch carry on. Dean was just as clueless as his mother about the last few minutes' events, so he consulted the blackened mass laying on the floor.

"What the shrivelfig is going on?!" Dean inquired, aiming a kick at Seamus.

He snorted, half in indignation and half in amusement. "I was trying to do my potions homework..."

"And let me guess... you added just a little to much ginger..."

"It just blew up! I was following the instructions in the book precisely, I swear. Well, I might've added an extra bat spleen when it wouldn't turn powder blue, but -"

"You shouldn't be allowed anywhere near a cauldron. Even looking at a potion book might blow up the whole street!" Dean was hit with a scorched old copy of The Standard Book of Spells, Grade One by Miranda Goshawk.

Half an hour later, Dean had a bag of Greta Catchlove's Frozen Flobberworm Fritters clutched to his head while Mrs Finnigan tried frantically to explain what had happened to Dean's Father.

"I am so sorry - We don't get many muggles around here - I have spells in place - This is a magical shop, can't just have just anyone walking in for their groceries - Muggle repelling charms -" The witch looked mortified.

"It's alright, Mrs Finnigan," soothed Dean's mother. "No harm done." Dean's father nodded, but didn't look entirely convinced.

"Unlike poor Dean. Oh, dear! Seamus, I really hope you've apologised..." Her voice had a surprisingly steely edge to it for such a small woman.

"Only about a hundred times," Dean grinned at Seamus. This was the truth, but he looked grateful all the same.

Once Mrs Finnigan had mended the house - Dean was amazed at the way the bricks slotted back together with a few flicks of her wand - Dean's parents left. The minute he'd seen Seamus, he'd known he would have a brilliant time at the Finnigans', so he wasn't too upset about leaving them.

The Finnigans had the best house Dean had ever seen. From the outside, it looked plain and box-like, with faded posters of muggle products covering the shop windows. A little embarrassed, Dean thought he would never have gone in there to buy muggle goods - but Seamus said, "it's designed to look awful. Another anti-muggle measure."

Dean thought that any muggle who walked into the Finnigans' shop - Bryne's Brilliant Bargins - would've had the shock of a lifetime. The pokey shop was lined with shelves, which were stacking themselves with all sorts of produce Dean had never seen before. He ducked swiftly as several bottles of Mrs. Shower's All Purpose Magical Mess Remover flew past his left ear but then had to sway back as tubs of Professor Bandywart's Bubotuber Acne Treatment nearly took off his nose. The whole shop smelled like a mixture of the Hogwarts potion ingredient store cupboard and Professor Trelawney's sweet, musky classroom, but these scents combined to make the most homely, comfortable feeling imaginable to Dean. He would've happily stayed for hours examining each of the wizard products in turn, but Seamus was pulling him upstairs for a goblet of cool pumpkin juice and cakes, and realising how hungry he was, Dean ran after Seamus.

Notes:

Mrs Finnigan is called Aislin (pronounced Ash-ling, hence Ash), a traditional Irish name which comes from aislinge, which means "a vision" or "a dream." Aisling is the name given to a popular poetic genre from the 17th and 18th centuries in which Ireland is personified as a beautiful woman in peril.

Bryne is a traditional Irish surname meaning "raven". The shop has this name attached to it from Seamus' maternal grandparents, who wouldn't've been called Finnigan - Seamus' father's name. I felt Seamus' relatives would've been quite predominantly Ravenclaws from the name that meant raven, so that may come up later on. The name is pronounced as Burn.

Mrs. Shower's All Purpose Magical Mess Remover is a product advertised at the Quidditch World Cup, but Professor Bandywart's Bubotuber Acne Treatment is my own invention based on the fact that Bubotuber puss cures acne. The fact that the tubs nearly take off Dean's nose is a little reference to the fact that bubotuber puss is suggested as an alternative to other spell treatments of acne, as Professor Sprout explains - Eloise Midgen accidentally removes her nose while trying out one of these treatments.