Jeff was still adjusting to the surreal reality of calling his six-year-old sister “Mom.” After testing out the Chronivac 4.0 device on her, Zoey had gone from a hyper little girl to a confident, 44-year-old woman with the smarts and instincts of a seasoned parent. She now sat comfortably in their living room, sipping a freshly brewed cup of coffee—her first ever—and flipping through daytime TV like she’d done it a thousand times before.
Jeff entered the room, laptop still in hand, the Chronivac emitter connected and idling beside him.
“Hey, uh… Mom?” Jeff said awkwardly.
Zoey smirked at him. “Yes, sweetheart?” she replied in a smooth, maternal tone.
“I still can’t believe this,” Jeff muttered, dropping into the recliner.
She chuckled. “Well, believe it. I’m the mom now. You’re the moody teenager I have to deal with.”
He rolled his eyes but smiled. “So… now what? It’s Saturday morning. We’ve still got the whole weekend.”
Zoey tilted her head, thoughtful. “What if we… invited someone to join us?” she said suddenly, a sly smile forming. “Maybe one of your friends?”
Jeff raised a brow. “Like who?”
“Your friend Sara. You said she’s your best friend, right?”
“Yeah. Why?”
Zoey gave him a mischievous look. “Don’t you think it would be fun if you had a little sister too? Maybe one that’s… four?”
Jeff blinked. “You want to regress Sara?”
“Just for the weekend,” Zoey said. “She’ll think she’s always been four years old. And with Unaware Mode active, she won’t even remember being older. When it’s over, she’ll go back to normal, just like me.”
Jeff hesitated. “That’s a huge change…”
“But temporary,” Zoey reminded him. “Come on. Let’s give you a taste of being the responsible one. She’ll be adorable.”
Jeff laughed nervously. “Okay, okay. I’ll call her.”
⸻
Fifteen minutes later, Sara arrived at their door, hoodie on, jeans slightly too long, and her backpack slung casually over one shoulder.
“Yo,” she called, stepping inside. “You said it was urgent?”
“Yeah, come in,” Jeff said, waving her into the living room. “I’ve got something crazy to show you.”
Sara’s eyes landed on Zoey, who was seated on the couch with a calm and motherly poise.
“Wait—is that your mom?” she asked, puzzled. “I thought she was out for the weekend.”
Jeff grinned. “Nope. That’s my sister. Sort of.”
Sara stared. “What?”
“I’ll explain,” Jeff said, leading her over to the laptop and the Chronivac device. “This is the Chronivac 4.0. It can change people. Physically, mentally. Temporarily. It’s completely reversible. Zoey used to be six this morning. Now she’s forty-four.”
Sara scoffed. “Right. And I’m a talking dog.”
Jeff smirked, typed something, and pressed enter. Instantly, his hair turned bright green.
Sara’s eyes widened. “Okay… WHAT?”
He changed it back. “So… we thought you might like to try it too.”
Sara tilted her head. “What kind of try are we talking?”
Jeff hesitated. “We were thinking… you could be my little sister for the weekend.”
“Wait, what?” Sara laughed.
“Just for fun,” Zoey added. “We’d regress your age to four. You’d be safe, happy, and unaware of anything being different.”
Sara blinked. “You’re serious?”
Jeff nodded. “Totally safe. You won’t even remember being sixteen while it’s active. You’ll just think you’ve always been a happy little kid.”
Sara paused. Then slowly, a grin spread across her face. “Okay… that’s actually kind of hilarious. Let’s do it.”
Jeff activated the scanner. Sara stood still as the device collected her data. Once done, he selected Age, dragging the slider from sixteen down to 4. He enabled Unaware Mode, set the timer for the rest of the weekend, and clicked Save.
A soft chime echoed.
Sara flinched. “Whoa… something feels weird,” she said.
Her fingers twitched. Her sleeves started to sag. “Wait, my sweater’s too big…”
She looked down just as the transformation began.
Her arms shortened slowly. Her hoodie began to drape over her body like a blanket. Her legs pulled inward, jeans sliding down her shrinking hips. Her stance became awkward, her balance shifting.
“Jeff?” she said nervously. “I think… I think it’s working.”
Her fingers grew chubbier, softer. Her voice pitched slightly higher, her speech slowing. “My… my pants won’t stay on…”
She kicked off her shoes, which clunked to the ground. Her jeans bunched at her ankles and collapsed. She stepped out of them clumsily. The hoodie now reached her knees.
“Why does everything look so tall?” she asked, voice now innocent and curious.
Zoey whispered, “She’s around seven now.”
Sara giggled suddenly. “I’m gettin’ tiny! Weeee!” she sang, spinning in a circle.
Her limbs shrank again. Her face plumped. Her socks slipped loose. “I wanna play!” she squeaked, voice slipping into full toddler cadence.
Then she gasped, stumbled, and landed on her diapered bottom with a plop. Her hair had shortened into two messy pigtails. Her eyes were wide and unfocused.
“Where… where my hands go?” she asked, tugging at her too-long sleeves.
Another wave. Her balance faltered completely. She let out a hiccup, blinked, and looked up at Jeff.
“Brudder?” she babbled. “Why you so biiig?”
Jeff crouched down. “How old are you?”
She held up three fingers. “Dis many!”
A soft giggle escaped her lips, followed by a yawn. Her eyelids drooped.
Zoey stepped forward and picked her up gently, holding her against her chest. Sara snuggled close, thumb in her mouth, eyes fluttering shut.
“There we go,” Zoey whispered. “You’re just Mommy’s sweet baby girl now.”
Sara murmured softly into Zoey’s shoulder. “I wuv you, Mommy.”
Jeff stood there, staring in awe.
His sixteen-year-old best friend… was now his sleepy, clingy, three-year-old sister.
And she had no idea.