Dipper Gleeful disdainfully drank from his mug of coffee, chastising himself for allowing his sister to prepare his drink. She always diluted her coffee with milk, and sugar, and cream, and anything else that struck her fancy as she went. He, on the other hand, preferred the bitter taste of black coffee. But his dear sister had been so very excited to make his coffee for him, and he was loathed to disappoint her.

"Do you like it, brother dear?" she asked him was an expectant expression.

He nodded silently and rose, placing his still half-full mug into the sink.

"You didn't finish."

"I have other things on my mind." He began the long walk to the basement laboratory. It used to belong to his Great Uncle Stanford, but the twins had since taken care of him and his brother, so the space was free for Dipper to use for his own experiments.

She followed after him. "Penny for your thoughts?"

He really did not have the time for silly colloquialisms and "small talk". "My thoughts cost far more than that, sister dear."

"Our shows are quite popular. I'm sure I can afford it," she replied instantly.

Dipper stopped and turned to face his sister. He opened his mouth to tell her to leave him alone but thought better of it. She was, after all, his sister. The last thing he wanted was for her to be upset with him. He began walking again, on his way to the basement.

"Well?" his sister followed him.

"You will have no interest in what I will be doing."

"Which is…?"

"A lot of mathematical calculations. If you join me you shall be bored out of your mind."

Out of the corner of his eye, he could see his sister pause. She turned and walked back down the hall muttering something involving the word "nerd."

Dipper Gleeful never thought of himself as a "nerd", no matter how many times his sister insisted he was. To him, "nerd" implied braces and glasses, and an affinity for dungeons and dragons. None of those applied to Dipper even remotely. He just preferred science to...most other things. It was based completely on facts, and everything had its correct answer. No room for uncertainty. It was comforting.

Besides, watching colorful liquid bubble in an Erlenmeyer flask was quite aesthetically pleasing, as long as you were wearing proper eyewear and knew what, precisely, was bubbling and why. Every question always had an answer in his laboratory. And those that did not, were pondered over until an answer was assigned to them.

Dipper knew his sister had been crestfallen that he had not included her. And truthfully, things may have been more entertaining with her around. Usually playing music softly in the background was enough, but strangely, he found the entire laboratory insufferably boring that day. After giving himself an hour and a half, he found he could not bear being in the basement any longer. Irritably, he left to find his sister.

Mabel Gleeful was brushing her long hair at her vanity when Dipper entered the room. He nodded hello to her, and she nodded back without turning around. Mabel spun around to face him just as he lowered himself into a chair.

"Miss me?" she asked.

"As if," he scoffed. As in, 'as if he would tell her yes'. He and his sister had been through so much together, and truthfully, he couldn't stand to be away from her for very long. She was the same way, of course. Dipper knew that this codependency was a problem to be addressed, but he'd been putting it off for months and did not plan to stop doing so any time soon.

Mabel turned back to her mirror, and Dipper selected a book from her shelf to read in the meantime. They didn't exchange another word, but they didn't need to.

A few hours later, the doorbell rang, which is an extremely unusual occurrence. Dipper exchanged a look with his sister and they simultaneously got up to answer the door. "I shall open it, sister dear," Dipper said. Just in case the person on the other end of the door was not the friendly sort. Mabel obediently took a few steps back as he turned the knob.

The boy on the doorstep wore a hat similar to Gideon's, but his hair was not the same unmistakeable white. He only wore one sneaker and his clothing was disheveled and muddy. Dipper blinked at the boy in confusion. He seemed...strangely familiar. "What do I.." Dipper began to mutter to himself. Next to him, his sister let out a shocked gasp. And that was when it clicked. Dipper recognized the boy from his reflection in the mirror every day. On almost all accounts, they were identical, right down to the birthmark on their foreheads. The biggest differences were the clothing and the fact that this boy seemed younger than Dipper and his sister.

But...what was this doppelganger doing at their doorstep?