Flying With Flaws
"You know my son?" She asks, very disbelieving, because her son, as far as she knows, is trying very, very hard, fighting with his wife about it every goddamned day, to get out of the life, for his daughter's sake. And this boy looks about as in the life as one could possibly get. But then, the strangest thing happens, Allison comes up behind her asking:
"Gramma? Who i'sit?"
And the boy's face melts, "Awwww," he coos, "Ally! You're just the cutest little thing, aren't you!"
Allison blushes brightly, "Umm, hi?"
"Hello, there. My name is Stiles, I know your daddy, he talks about you all the time, did you know that? He loves you the bestest out of everyone in the whole world! And why wouldn't he? Look at you, those pinchable cheeks!" And all of her doubt flies out the window. Allison is one of the Argents better-kept secrets, because Chris has been adamant about that, if the boy knows of her Chris must trust him immensely.
[Or: The one where Chris, Stiles, and Peter go back in time and fuck shit up, and scoop up a little Allison along the way.]