November 3, 2030

  Gamamusa kept a close watch on Goyeun’s movements. Goyeun frequently visited the research facility for her work on biofuel development. She spent time in a storage facility with microbial cultures, cultivating digestive mocrobes from herbivorous animals. In particular, she was researching microorganisms related to animal digestive systems and methane gas. She felt an exceptional sense of accomplishment when studying digestive microbes, a result of Gamamusa sending dopamine signals. Over the past few days, he had honed his ability to subtly adjust the dopamine levels so that Goyeun wouldn’t notice. She brought a few microbial samples home, including some that Gamamusa had targeted.

  'Creak…' The cabinet blocking the basement opened, and the basement door swung open. Gamamusa slowly climbed the stairs, passing by Goyeun’s bedroom. Goyeun was sleeping like a dead body, her brain continuously releasing serotonin. He entered the study, which had been converted into her research lab, and extracted microbes from the glass petri dishes containing the samples, transferring them into a glass flask with culture medium. He then carried it down to the basement. Gamamusa placed the microbes into a flask containing an acidic substance and shook it well. He removed the microbes and observed them. The microbes had dissolved well. Next, he added grass to the microbial sample and examined it under a microscope. The results showed the microbes breaking down the dietary fiber in the grass. “Bingo.”

  …

  Gamagogi had been quiet since boarding the plane. When the in-flight meal was served, Gamamusa picked up the tray and passed it to Gamagogi. Gamamusa hesitated for a moment, then lifted a piece of salad from his tray with a fork. “Wait.” Gamago looked down at Gamamusa. Gamamusa gazed back at him, puzzled. “...You asked the question before. Why did the soldiers that ate grass starved to death.” Gamamusa nodded quietly. Gamagogi picked up a piece of salad with his fork and showed it to him. “This is called grass. It contains dietary fiber. Dietary fiber is a structure made of multiple particles of an energy source called ‘glucose’ linked together.” Gamagogi then scooped up some rice with a spoon. “This is called grain. It contains a lot of carbohydrates essential for humans. Carbohydrates are a simple structure of a small number of glucose particles linked together. Meanwhile, the fruits we eat are made of sugars, which are two glucose molecules connected.”

  Stolen from its rightful author, this tale is not meant to be on Amazon; report any sightings.

  Gamagogi set the food down. “The point is, in a nutshell, ‘all plants store energy in the form of glucose.’ Of course, this glucose is stored in various complex structures, but if you can digest these structures and convert them into glucose, you can use it as an energy source.” Gamamusa was amazed by his words, and Gamagogi continued. “...Omnivorous animals like humans can only digest carbohydrates and sugars. Digesting complex dietary fiber is something only animals with two stomachs, like cows, or those that eat their own feces for a second digestion, like rabbits, can do. We call this ‘rumination.’” Gamago gave a faint smile. He seemed to enjoy this topic.

  Gamagogi pulled out a water bottle containing the cloudy gel from his carry-on. “...This is lactic acid bacteria taken from a cow’s rumen that digests grass. Since it thrives on digesting grass, it’s quite finicky about surviving outside the stomach.” He picked up a piece of salad, placed it in the bottle, and shook it. The salad slowly began to brown in the gel’s weak gastric acid, broken down by the microbes. “...Pretty cool, huh?”

  …

  Baek Hyung-jin touched the grinder. The ceiling of the grinder had a hole where the grinding mechanism was inserted, and a pile of hay was stacked at the bottom. “...What’s this device for? Don’t you just need gastric acid to digest?” Jang Cheol-dae nodded. “...Of course, to digest grass, you only need gut microbes. If you ferment the grass for a very long time, it can become carbohydrates. But if you ferment it for that long, it rots and becomes inedible, so we mimic the cow’s grass-chewing process by adding amylase and running it through a grinder.”

  Baek Hyung-jin turned to Jang Cheol-dae in surprise. “...Eat it? Wasn’t this machine for making biofuel? Or is it for making feed for cows?” Jang Cheol-dae shook his head. “How many times do I have to say it? Cows can eat feed just fine without this device. The ones who can't digest this grass and eat it aren’t herbivorous cows—they’re omnivorous humans.”