Jake was on out above a baseball stadium trying to stop the Huntsman from getting hold of the Uchrono Hourglass, a device capable of traveling back in time. Unfortunately, like most of his missions, he had to keep it hidden from his dad, who thought that he was still studying at the library. But after Jake finally got a hold of the Uchrono and fell into the stadium, he ended up catching a baseball, putting him on TV. Coincidently, the Long family was watching that exact same game.
Unable to defend himself without exposing his family's magical secret, Jake was grounded for two weeks. Bummed out about being grounded for something he had to do, Susan brought Jake up to the basement to show him something.
She opened up an old box and pulled out an old photo album, and turned to a certain page. On this page it showed her and Jonathan at the Halley's Comet beach party on June 27, 1986. On the back of that certain page, a letter that wasn't even opened. Susan when on to explain that she was going to give Jonathan this letter on the last day of school, and explain her family being a dragon, the existence of magical creatures, everything. However, she did not give it to him, saying some secrets are better kept secret.
In the next scene, Jake headed off to the shop, to give the Uchrono to Gramps. But just learning he could use the device to time travel with, it gave him an idea. He turned the knobs, and got ready to use it. Fu Dog spotted him, and ran over to stop him, but before you know it, both enter into June 27, 1986.
Jake explained to Fu about the letter his mom was suppose to give to his dad. All he had to do now is make sure he got it. The two of them head off into his school, and search for younger Susan and Jonathan. Once they find him, Jake stole the letter, and shoved it in Jonathan's locker. However, from outside the school, Jonathan was freaking out about the letter Susan addressed to him; all the way to the point where they break up. At first Jake figured this fight won't last very long, but he then realized if he doesn't get them back together, he and his sister would not exist.
The new plan now was to get Jonathan and Susan back together. Future Jake and Fu headed to the shop, to see if younger Gramps and Fu would help them in some way. Fu sent off his younger self to Atlantic City, and Jake pretended to be the Canadian Dragon named Beyonce Timberlake to prevent Lao Shi from knowing they were from the Future. However when future Fu tried to convince him that he needed to help get Susan and Jonathan back together, he laughed and cheered saying he was waiting for the day when his daughter would dump him.
With the current plan foiled, Fu thought up plan B. He decided that he'll bring Jonathan to the Halley's beach party, and Jake would bring his mom. The two would meet each other there, and maybe it would help them get back together. Unfortunately, this plan also failed when Susan headed home before Jonathan arrived at the beach.
Now with Jake, Jonathan, and Fu there on the beach, Jake decided to tell him the truth. But as any person would say they were from the future, Jonathan didn't believe him. He proved himself with a picture he had from his pocket, and turning into a dragon. But only terrified him to the point of fainting.
Just as they figured things can't get any worse, they do. The younger Huntsman charged up to attack Jake. Jake put up a fight, but the Huntsman set off a bomb that blew Fu and him down into the sand. While they were distracted, the Huntsman stole away Jonathan's body, and took him into a submarine.
With his dad captured, and the sand in the Uchrono Hourglass almost empty, the two headed back to the shop. There, they convinced Susan and Lao Shi to help them rescue Jonathan from the Huntsclan.
The four of them useed an enchanted compass to find Jonathan and the Huntsclan's lair. There they snuck inside, and kick some Hunts-butt! But in a total accident, Jonathan got hit by the falling roof, and fell down unconscious. Jake and Gramps took down the Huntsclan, and everyone got out safely.
Back on the beach, Jonathan just started to wake up form his injury. With this moment, Susan and Jake lied about the whole dragon situation just for his sake. With everything back to normal, the two lovers took their Halley's Comet beach party picture just as Jake and Fu headed back into the future.
Back in the present time, Jonathan told Jake that he felt bad about punishing him. He and Susan talked it over, and decided just to give him a warning this time. Jake as super excited, but started to bum out again when his mother found out he was time traveling from the photo her and Jonathan took on Jone's beach. Apparently, Jake was right on the side, when the picture was taken. Once again, Jake found himself grounded for two weeks by Susan Long that means no TV and no video games.
- Jonathan Long: Your mother and I talked about your grounding…, we've decided to let you off with a warning this time. Have a good day, all.
- Jake: Thanks, Mom.
- Susan Long: I just hate seeing you get punished…? What the…? Time traveling? And on a school night? You are grounded, Young Man. No TV. No video games. Two weeks.
- Jake: Aw, man!