As I'm sure everyone is aware, the accepted idea is that everyone knows about time travel after the movie, hence why TMPaSS exists. The creators even said they 'started the show to capitalize on that' (paraphrased) …whatever that means.

But, if you are a BIG fan, like me, then you've also hopefully read every single book that was written. And in the Junior Novelization, canon possibly* diverges… In that book, they go back to before any of the whole time stuff happened, woke the Petersons from their trance, and the party was successful.

"We returned to the dinner party before any of this happened, and I snapped the Petersons out of their trance. The party went on to be a roaring success. Penny and Sherman became best friends, and she accompanied us on many adventures in the WABAC."

The Big Golden Book also suggests this, the end illustration shows them at the dinner party again, happily eating and talking. The text says:

"Sherman's idea worked, and everything returned to normal. But it was only the beginning of Mr. Peabody, Sherman, and Penny's adventures."

Now the BGB doesn't imply anything other than Penny regularly starts coming with them on their trips. The JN states that explicitly but also implies a little more. They definitely time traveled again.

*I say possibly because there's no solid proof that didn't happen in the movie. We have a large time jump from when they emerge from the future wormhole to the next day going to school. There's nothing to say they didn't go back and do what the books (or this story) said in that time. And, if they did, that means no one would know about the WABAC or time travel.

The purpose of this story is to create a 'fork in the road' if you will. This idea came from Time is a Matter of Perspective. I have a couple new ideas for it, as you can see from the recent chapter update, but they require that the WABAC and time travel still be unknown to everyone except the trio. This could also explain any other stories where the WABAC and time travel was unknown in time periods past the movie.

The ending does not suggest a continuation, this fic is complete and standalone. The ending is that way because I like to keep continuity with as many other fics as possible, and there have been many great ones set after the party dealing with Peabody and Sherman's relationship.

Now, I kid you not, this kept me up for two hours racking my brain trying to think of a way to make this work.

Of course, my goal was to make sure no one other than the trio knew about time travel. Now, we start at the point in the movie where Sherman and Peabody emerge from the future and fly over the gathered police force and the Petersons. At that point, they would then travel back to the point where Peabody put the Petersons in a trance. Now, this is all fine and good, but remember everything else is still happening. Past Peabody and Sherman just left, and Grunion, past Peabody and past Sherman are still on their way. One restriction I put on it is they can't combine their cosmic doubles again, that would just cause the climax of the movie all over again. And this is really why all my ideas failed. No matter what, we'd always have two of any person. I'm trying to reconcile the book canon with the movie canon, and despite most of my time travel ideas failing, I think I still did it.

Ultimately, I settled on an idea that doesn't involve time travel at all, (and is a slight Dues Ex Machina, but what else am I gonna do?) which I now present to you…