Re-introduce yourself... as her biological father.

The quiet taps of steel utensils on plates is the only sound allowed at breakfast, and these motherless, wifeless mornings are still awkward enough to stifle any casual conversation. A standard American household might use the television to substitute for meaningful dialogue for such a meal, when and if the family ever ate together like this. Such is impossible for you. Isabella's life is one of cautious deprivation, built on media blackout and carefully described dangers. As far as your stepdaughter is concerned, unrestricted television leads to injuries, possibly even to people with her baffling condition; it's barely a lie, given contemporary ads. Your former wife went the extra mile to extend this blackout to society, cutting Isabella off from friends one by one as they made... questionable recommendations to her, and once even endangering her at a zoo. By now, Isabella has no real friends unless she reaches out to them, and even then she knows it to be deadly to do that without supervision. With so many lethal, almost primitive fears attached to common social needs, Isabella has grown quite attached to her limited family, and barely rebels against this for the same reason a teenager wouldn't "rebel" by jumping off a skyscraper: because she "knows" it can, and probably will, end her life. You always wondered what the endgame was for so stifled an AGS victim, given society's otherwise laissez-faire handling of sufferers of this disorder.

But you don't wonder this anymore. You are her endgame, now. You've brewed this twisted plot for all of a few days, but when you get right down to it, Isabella is more or less an Etch-a-Sketch: if the image doesn't come out quite the way you like, a firm shake of her entire reality could let you start over. The thought brings a guilty smile to your face as you slowly eat. You watch her like a predator, savoring her ill-dressed, tight little body, the glisten of bacon grease on her lips coupled with crumbs from her buttered toast, and her occasional lick of succulent lips with an innocent tongue. Your former wife did an amazing job, keeping her safe until now.

Isabella finishes her breakfast first, wiping her mouth with a napkin and dutifully takes her plate and utensils to the sink. You rise with her, your breakfast mostly eaten. You stare down at her generous rump, sizeable but proportional to her fit body, gripped and shown off by panties that were mostly stuffed in her crack. You don't touch her; not yet.

"Isabella," you whisper behind her, and she nearly jumps from your unexpected proximity.

"Y-Yes?"

"When you're done with the dishes, we need to talk... upstairs."

Moments later, Isabella knocks on the door of your master bedroom, made mostly barren now that Ashley's effects have all been stuffed away in the attic. "Come in... sit down here next to me." You tap on the edge of the bed. You've decided to put on pants, given that you can no longer command your erection to ignore the brewing plots in your mind, but she remains ever in that shirt and panties, likely until she finally takes her morning bath. She plops herself carefully on your bed, and casts a sad glance around, likely imagining all of her mother's perfumes and widgets still strewn about. "Isabella, there's... there's something your mother and I were keeping from you, for your own safety." She looks alarmed, but nods. "I need you to listen very carefully, and to understand that what we did was absolutely for your happiness and safety..." You inhale dramatically for the next lie. "Isabella... I'm your father."

She freezes as she braces, but then blinks in obvious confusion. "Well, I know that Lenny, you've been my-"

"No, Isabella, I'm your... I'm your biological father." Her eyes nearly bulge out of her head as her reality, of being miracled into her mother's belly, is shattered. "The immaculate conception your mother described... it's a metaphor. It's actually fairly common in couples in our situation, and you would've found out sooner if your... condition... didn't interfere."

"A... A metaphor?" She knows that word well: they're mostly beyond her. Metaphors skirt too closely to lies for those with AGS, and so there's often a majority chance that they'll take them as blunt truth. "So... So did I... did I take it too literally?" You nod, frowning. "I'm... I'm..."

"I know this is a lot to-" Your words get cut off as your beautiful stepdaughter, now daughter, jumps across the bed to hug you. Her body trembles as she presses herself tightly against you, and you hear her sobbing softly. "I-Isabella, what's wrong?!"

"I'fm fuft fo rphyy," she mumbles into you. Pulling away, she repeats herself, "I'm just... so happy! Lenny... no... daddy! I thought... with mom g-gone... I didn't think I had any..." She cries as she kisses you on the cheek, and begins wiping her face. "I'm... oh wow! This is... this is so much..."

You nod... and take her face in your hands, wiping her tears away yourself. "We were going to tell you when you turned twenty. What she told you about how you were conceived... honey, it's a metaphor for when a couple has a child, but doesn't marry right away... it's a very secretive, embarrassing thing for the parents, which is probably why you never realized it before." She absorbs your words, smiling and crying all the while. "So... so now," you whisper, "we can finally live and be together the way a father and daughter should."

She looks at you quizzically, laughing in your soft grip. "Don't... we?"

You shake your head, deepening your frown. "There are secrets words and deeds that fathers and daughters keep; secrets no one publishes or talks about, and that must never be talked about with anyone, ever. To do so," you sigh, "would cause brain cancer in anyone involved, be they the speaker or the listener."

Her jaw drops. "Brain cancer?! How does- what does- that's horrible!" You've lived with this girl, and her AGS, for almost five years... and it still baffles you how readily it works.

"It is, but we don't have to worry about that. I'll teach you all of these secret things that fathers and daughters share, so you'll never have to worry about endangering anyone else... but to be safe, you need to avoid online friends until you're sure you won't accidentally kill them and yourself."

Everything is carefully engineered. The words you choose, the phrases, the options as opposed to the requirements: she knows she'll kill herself and others with cancer if she reveals any of these soon-to-be-learned familial "secrets". No one shares this with anyone else for obvious reasons, and from there she can build her own narratives about why this is true, and how all of her female friends must have gone through the same. AGS would build these narratives for her, and bridge whatever gaps your obvious, stupid lies made. She nods, eyes glistening, and forces a smile. "I understand... but I'm still happy, I... I never knew I had a father."

With her face still in your hands, you lean forward and kiss her on the mouth. Her eyes go wide as your tongue penetrates her lips and taps against her teeth until they open, first to gasp but now to allow your invasion. Your tongue probes hers, and it wrestles back in a protest more erotic than denying. You let your hands roam along her neck and the back of her head, but no further... for now. You withdraw from the embrace of lips, a line of spittle connecting you both. "That's the first secret." She blinks at you, horrified. "A father and daughter kiss deeply and intimately, more than even lovers. It's innocent between them, and clean."

Her horror melts away to surprise. "Oh my... really? But I felt..." She glances towards the mattress... and her hands ball into fists as they settle in front of her crotch, as if to hide it.

"If it feels good, that just proves we're finally connecting as father and daughter," you declare with a smile. "When we're truly connected, it will actually feel very similar, even exactly like... sexual pleasure." Her eyes go wide once more, but once again this new "fact" is absorbed as true. "This just means that we're finally, truly bonding as father and daughter... It is innocent, and you shouldn't hold back on whatever this feeling tells you." You clear your throat, and prepare to deliver the final blow. "That bonding will fill you with joy, and you'll come to crave it. This is natural. It is unhealthy to deny it, so you must accept it and state whatever feelings or desires arise, openly. There is nothing to be ashamed of, between us."

You give her a softer kiss without tongue, and her head leans to receive you. Withdrawing you look over her face with a hunger ill-matched to hers of child-like adulation. You have... so many secrets to show her.