Unfortunately, Severus caught a glimpse of Arabella rounding the corner of the pavement just as he was leading the boys up to Number Four. He cursed internally, sent the boys straight upstairs to play in their room, and called to Petunia that he'd be "back in twenty."

So saying, he snatched a frizzy gray hair from Arabella's jacket she had left on the hook this morning, inspected it to ensure it was human, then disapparated and reappeared in his home in Cokeworth. He went straight to his warded potions cabinet and extracted his small supply of polyjuice. He measured out the smallest dose possible, enough to transform for only ten minutes. He added the hair and watched the potion turn a sort of pale ochre color. He pinched his nose and downed the potion with a grimace. While his skin wrinkled and bones shrank, he set about transfiguring his muggle menswear into a floral print dress of the sort Arabella favored. He didn't bother looking in the mirror: he had taken the potion to mask his scent around the kneazles. His appearance didn't have to be perfect by any means. It only had to confuse the felines and keep them from recognizing him after the fact.

He apparated to Arabella's living room next, sending cats running and hissing in all directions. A few turned to growl at him, not fooled for a moment that he was actually their mistress. No matter. Any distress and abnormal behavior would be easily chalked up to the fire. He marched to the back of the house and opened the door to the yard, then went upstairs, figuring it would be most believable for the fire to start in the attic, since he didn't want to ruin the squib's kitchen or trap any of her cats upstairs accidentally. He barely glanced inside the attic, just cast a weak Incendio at the wall holding the light fixture, shut the door, disillusioned himself, and apparated into Arabella's neighbor's bedroom instead, since he could tell it was empty from here. He waited long enough to see a trickle of smoke out of Arabella's attic vent, then quickly dialed the fire department to report his own crime before apparating back to Cokeworth to wait out the polyjuice. Once he had returned to himself, he returned to Number Four Privet Drive.

Petunia looked up as he entered the room with relief. "Am I glad you're here. Mrs. Butler who lives on Magnolia Crescent called to let Arabella know the fire trucks were at her house! Poor thing had to rush back just now, all panicked about her cats. They're her livelihood, you know. I suppose the profit margin is why she puts up with the hair and the smell..."

"I know. I set the fire in the attic." He sat down on the couch.

"I beg your pardon?"

"Not badly, just enough for her to have to run over there to sort it out with the fire crew, while we talk. I opened the door so the kneazles could escape. Even if her insurance isn't good, I can help magically with any repairs she might need. Or Albus can do it, since she's on his payroll. Remind me to buy her some extra cat treats or something."

Petunia blinked at him. "What on earth happened for you to decide it was a good idea to commit arson?"

"It's about Harry. Something at the park that I don't think Albus Dumbledore and therefore Arabella should learn of just yet."

Petunia's outraged expression quickly morphed to one of attention and worry. "What about Harry?"

Severus took a deep breath. "As it happens, he can speak to snakes. Had one quite literally wrapped around his fingers at the park."

Petunia made a face, clearly not fond of reptiles. Then she frowned again. "You mean, he can talk to snakes like you said Moses could. The magical snake language."

"Yes. It's called parseltongue."

"Right. And this is a problem because...?"

"Because despite what I told you about Moses, parselmouths are not well-liked in Britain, because the most well-known family carrying the trait here were notorious for hating muggles and the last known member... was the Dark Lord who murdered Lily."

Petunia's mouth fell open. Dahlia stirred and grumbled in her arms, and Petunia patted the infant's back. "Okay. Okay. I'm a gossip-monger. I can see how that would be deemed significant. Particularly with how superstitious you lot seem. But how important is this really? Is Harry in danger?"

"From this talent itself? No, not at all. The danger is abstract as you say, a matter of how other people will read into it. I just didn't want him to immediately start telling Arabella about it. Hopefully he forgets or has something else on his mind by the time he sees her tomorrow."

"Is Albus Dumbledore so much of a superstitious fool as to judge an almost-five-year-old on what you told me is an innate ability?"

"Well... I don't think he would be so idiotic as to regard parseltongue as an evil omen and stain on his character, but I do think it would spark his interest in a way we'd rather avoid. It's not a common trait. It's inherited, and I never heard of any parselmouths in the Potter line."

"And Lily obviously wasn't one either. Who knows, though? Maybe it's a recessive trait and both Potter and Lily did carry it if you follow the geneologies back far enough. Didn't you say a lot of muggleborns can actually trace their ancestors back to squibs like Arabella?"

Severus nodded. "It's possible, of course." Statistically improbable from what little he had learned about genetics from the books Petunia had sent his way as part of his anti-blood-purity-five-year agenda in Slytherin House. But possible.

"How else could Harry have gotten it if it's inherited? Don't tell me magical, er, imprinting, is some weird side effect of surviving a murder attempt."

Severus hesitated. "Well, we don't actually know if it is or not."

Her gaze sharpened. "You don't know?"

He threw up his hands. "Harry's case is unique. Surely we talked about it at some point? There's never been a recorded survivor of the killing curse before."

She raised an eyebrow. "Are we sure it was the killing curse he was hit with, then? I thought no one else was in the house besides Harry, James, and Lily. That's what Dumbledore's letter implied, anyway."

He hesitated again. How was everyone so sure it was the killing curse and not a ritual of some kind that backfired? Dark magic left traces, but it would be hard to verify the Avada Kedavra as culprit without another historical survivor to compare the stigmata to. Surely it wasn't an assumption simply because that was the Dark Lord's signature murder method! Did they find the Dark Lord's wand and test it? Did the Potters happen to have a family portrait observing the crime? He hadn't noticed one in the brief moments he had been in the house before Black and Hagrid had arrived, but it could have been in the other room where its occupants could only hear the attack, not see it. Maybe Albus used Legilimency on baby Harry to see the memory of what happened. He shuddered at the very thought. Regardless, "Albus is sure. There are ways. I wasn't involved in the investigation, but I do trust him not to lie about that."

"Fine. In that case, how do we make sure this is inherited and isn't some weird side effect from that night? I want to know, Sev. If there's one long-term effect of that awful attack, there could be more. I want to know my nephew is safe."

"We can research yours and Potters' ancestry, I suppose. We should do that anyway - proving a parselmouth ancestor or two will go a long way to reassuring the wizarding public this is normal and not a cause for alarm if and when it does get out. And that's the other reason I wanted to talk to you about this right away. It would be unfortunate if Harry were to tell Arabella about the snake, but not disastrous since Albus for all his manipulations is still well-intentioned. If Harry fails to keep this secret as he gets older, however," he paused significantly, "then other interested parties who are stupid and superstitious enough to believe blood defines one's character will take this as an omen that Harry is destined to be a Dark wizard. Idiots on the Light side will shun him, while Ex-Death Eaters who weren't caught might try to recruit and control him."

"Damnit," Petunia muttered. Strong language for someone who never swore due to all the small children around her. Muffled laughter and pattering feet across the ceiling above them filled the temporary silence. Petunia sighed. "We have to teach a toddler to keep secrets. Consciously, not just 'this behavior is for home, and this is for public,' like wearing pants and inside voice and when it's okay to take off shoes and so on."

"Unfortunately."

"Which no doubt means he'll ask more questions, and we'll have to tell him more about magic and what happened to Lily sooner."

"Yes."

She looked down at the tiny baby in her arms, who had been sleeping throughout the whole conversation. "They grow up so fast."

Author's note: Because a little light arson is funny, both in canon and in fanfiction. And Snape will not stop treating the raising/protecting of children as a war campaign.

Wasn't until I was writing this chapter that it occurred to me how odd it was that everyone was so sure Harry had survived the killing curse when there were no living witnesses and every other discussion said the curse left no traces. Besides what forensic possibilities I listed, people have argued the Trace could be used, since it could identify Dobby's hover charm in Harry's vicinity, but I don't think that holds water or else the Ministry wouldn't have had any problem identifying things like Imperius curses happening in households with children during the war. The Trace in such a scenario would have operated as an early-warning system for the auror department all around the country, and the only way to get away with crimes in households with children would be to boycott any Dark spells.

Thanks for the reviews. I'll aim for another update in a week or two.