Calvin wants to know if Hobbes wants to go time traveling with him. He has built a time machine. It's a box with "time machine" written on the side. Hobbes says it looks like his transmogrifier. Calvin says it does "to the inattentive, brainless layman". He points out that you crawl in the bottom of the transmogrifier, whereas you crawl in the top of the time machine.

Calvin tells Hobbes to put on his goggles, and they'll be ready to go. Hobbes wants to know why he needs goggles. Calvin explains time travel is not like driving down the street. There are vortexes and light speeds to contend with. Anything could go wrong. Of course they need goggles. Hobbes tries to get out by saying his goggles are in the bedroom. He tells Calvin to leave without him if he isn't back in a couple minutes. Calvin tells him to sit down. He has Hobbes' goggles.

They're now flying forward in time. Calvin sees they're approaching the present. He asks if Hobbes wants to go forward in time like they planned, or did he want to stop. Hobbes has had enough time traveling. He opts for home. Calvin tries to convince Hobbes to go a little into the future to see what Calvin is like as a teenager. Hobbes doesn't want any part of that.

Mom is gardening when Calvin comes over and tells her he and Hobbes went time traveling to the Jurassic period today. She asks what it was like. Calvin tells her it was scary, and they almost got eaten by a dinosaur. Calvin admits they were trying to go to the future, but made a mistake. Mom is glad he made it back. Hobbes is surprised that didn't faze Mom at all. Calvin reminds him that she didn't take the frogs in the toilet.

Hobbes figures if they're good snacks, it's okay to time travel. Calvin sets the dial for 140 million years ago, and off they go. Hobbes asks why they don't get younger as they travel back through time and disappear as they pass the day they're born. Calvin says he'd explain it, but there's a lot of math. Hobbes says he thought Calvin got a "D" in math.

Calvin runs up to Mom and asks if she knows where he and Hobbes have been. She says she saw him playing in a cardboard box out back. Calvin says that's what it looked like, but they really time-traveled to the Jurassic period and returned at the split second they left. That's why it didn't look like they left. He says they saw lots of dinosaurs. He asks if Mom will take some film to be developed. He'll pay her back when Time magazine coughs up for his story.

Calvin and Hobbes time travel to the future. They meet the 8:30 Calvin. The 8:30 Hobbes asks the 6:30 Hobbes why he always goes on these things.

The two Calvins go back to make the 7:30 Calvin do the homework. The two Hobbes' talk. One says this has to be the least efficient way to write a paper. The other says all this modern technology makes people try to do everything at once.

Mom asks if Calvin wrote his story. He says Hobbes helped, and he had to do a lot of time traveling. Mom asks if the story is written. Calvin says it is, but he hasn't read it.

Miss Wormwood asks Calvin to read his story. Calvin reads that Hobbes, the handsome tiger, saves the day. He reads that Calvin is a time traveling chowderhead. Miss Wormwood asks if there's a problem. Calvin says there will be for a stripey furball when he gets home.

At home, Calvin complains to Hobbes about the story saying Calvin tried to get out of writing the story by time traveling. Calvin complains the drawing was of three of him fighting. He says he was a laughingstock. Hobbes asks what grade he got. Calvin says it was an "A+". Miss Wormwood wrote the "tiger" narration was a clever touch and is glad he's finally applying himself. Hobbes thinks he should send it to the New Yorker.