Here's a basic plot I propose you to try :
A group of friends find a little device that is basically a time machine, bringing them in the past, but their bodies also got back to how they were at the year they go. The first trip is accidental, then things goes awry.
With the device either being taken away by a parent, or requiring a waiting time to recharge, or being disfunctional and not properly going to the year they want. Or the three at once.
And my starting piece :
Time
The wind was hollowing outside, and with each new squall the group of friends could hear the branch of a nearby tree strum against the wall.
In stark contrast to the angry winter, the bedroom they were in was very cozy. And the healthy amount of booze an pot they had brought sure helped to the warm atmosphere.
But more importantly, Lauren's old bedroom, with its large ceiling windows against the leaned roof had the major advantage of being the best way to observe the sky night safely apart from the icy wind.
There was a heavy comet shower exposed cted to occur that night. A sight you could only get the chance to see a few time in your lifetime, according to the news, and the group of friends sure was curious to judge by themselves.
The four of them were in college yet in different years. At 21, Lauren had finally settled with a serious boyfriend, Jake, whom she had met earlier in the year during a midterm binge of the Library's materials. As the assertive brown haired girl finished installing an old telescope, brushing some dust away, she sent Jake a satisfied smile.
"Look like it's all set up" she announced.
Answering with a little wink, Jake extended a hand to refill her glass with the content of the bottle he had just opened.
"I knew my gramps old telescope would be of use someday. The stuff spent the last decade in the attic, if not more." he said as their glasses tinted.
"Well, we shouldn't really need it until a full hour to see the shower if it goes as they announced, visible to the naked eyes and all, but I'm sure getting a closer look if we want won't hurt. Right, Lisa? "
On the other side of the room, her childhood friends Lisa and Scott were rummaging through the equally dusty box Jake had brought over with him, and the girl nodded absentmindedly before pointing something to the boy crouched beside her. Lauren smirked at the sight of the complicit duo enjoying a casual conversation between a few jokes and laughs. The three of them had knew each other since basically forever, and finally after some time looking around in their teens did her two light haired friends began to consider they could foster something more than just friendship. Still, both were too timid to aknowledge just yet. Sipping her drink, Lauren wondered with a smile if she wouldn't have to give just the right push tonight.
Her wandering thoughts were interrupted as Scott got his hands on something and asked out loud.
"Hey, what do you think that's for?"
Lisa raised an eyebrow, "Dunno, look a bit too modern for the rest of that retro bunch."
"Maybe it got mixed up."
Indeed, unlike the old vaguely astrology related stuff they had been going through, what Scott was holding looked like some sort of sci fi device. It was a thin rectangular piece of shining steel, with a screen on one side and two circular buttons below it.
"Found something?" asked Jake rhetoricaly as Lauren and him approached, curious.
Scott was about to answer, when the screen suddenly lightened up. He hadn't even noticed pressing his thumb against the screen, but as he removed it, they all saw the outline of his fingerprint briefly being outlined on it before fading out.
"Whatever it is, it's still working." Chuckled Jake as he leaned to press his own index on the screen in an expectant way, followed by his girlfriend. They watched as a bright light renewed the short lived process. "Must have some pretty solid battery.
" I suppose it's got something to do with astrology" said Lisa, eyeing the rolls of sky maps poking out of the box.
"Hmm, what's now?" wondered Scott out loud as a little message appeared.
It was asking "Do you want to proceed now with (3)?"
"Hey, wait!" hastily said Lisa. "Don't leave me out." She selected the negative before adding her own thumb, blushing.
"Geez, it's just a gadget, Lisa. No need to blush. " said an oblivious Scott, rolling his eyes.
A moment later, the same message appeared, this time confirmed.
To their disappointment, only a serie of years dates appeared going downward. It started with the current one, yet for some reason stopped barely more than twenty years down.
Laureen felt an idea popping in her head, and she shared it with her friends. "Hey, maybe it's every years there was an astronomical feat?"
Jake nodded, "Try the last time we got a full moon eclipse."
"Well, why not. When was that again, fifteen years ago or something?" he enquired.
Swipping out his phone, the young man immediately proceded to check wikipedia.
------
I'm letting you chose the year and age they will land in by changing if you want the exact number of years of the gap.
Does anyone want to continue with the next part? :]