[ WP ] The Earth does not rotate . One side always faces the sun and is in continual daylight . The other side is in eternal night . Cultures on both side develop around this .

Captain Norris was tired. It had been ten days since they crossed into the Black Side and three since they dropped off the kid, and the crew was on edge. It had been 10 years since anyone had attempted an expedition to the Dark Continent, and they always ended the same. Sailors would land on the eerily hot sand, collect plant samples, and dig some holes and pan rivers for precious metals or gems ( *never* finding a damn thing ). But it was only a matter of time before the natives came and attacked everyone. 
 
 `` Attack *the torch carriers*'', Sir William had said when Norris first tried to talk him out of this crazy mission. `` They always first attack sources of fire. I wo n't be needing a torch, so I wo n't have that problem.'' Norris had chuckled. He felt bad for the kid. Sir William Mason, at age 16, was the oldest person that had ever lived with Sun Sickness. His affliction was an incredibly common one that affected roughly one in ten newborns. Their weird little eyes ( if you could even call them that ) were incredibly sensitive to light and their skin blistered almost immediately in the sun. No amount of clothing or covers seemed to be completely effective at blocking the sun's effects, and children rarely lived to see their second birthday. It had become common practice to kill newborns with Sun Sickness to spare them from their few years of pain, and the High Priest had even endorsed this as a form of mercy. 
 
 But William's parents could not bear to kill their firstborn and resolved to find a way to allow him to live comfortably. They had a wing of their mansion completely sealed from the sun and hired blind servants and tutors to raise the boy in his own little world. When the time came to train him how to get around in the dark, everyone was amazed that he had completely perfect night vision. He grew up comfortable, but restless. `` I was living in a five-room prison when there was a whole half a planet devoid of sun,'' William had said through the little communication slit of his box ( the oddest piece of cargo Norris had ever hauled ). `` The Dark Continent is where I belong. I'm sure of it. What if the natives are just like me? The last sailor to see one described their eyes as like those of someone with Sun Sickness.'' 
 
 `` That was a terrified deckhand that caught a *glimpse* of a savage's face in near total darkness as he was high-tailing it to the shore,'' said Norris. `` That was 10 years ago, and we lost three men. It was bad enough that the expeditions never made any money, but this was the first one where we had fatalities. Nobody has funded an expedition since then. It's just wasting money for the chance to get shot with an arrow.'' `` Well, I'm paying you a small fortune for this mission,'' said William, `` And all you have to do is drop me off at the shore and wait in your boat.'' 
 
 That had been three days ago, and Captain Norris was not looking forward to Day Four. That was the agreed upon time to send a search party for the young man and Norris was seriously considering turning around and just lying to the kid's parents, telling them that he witnessed their son get killed by natives and there was nothing he could do ( a plan the crew had repeatedly suggested to him ). It was then that he heard the musket fire from the beach. One shot into the air was the signal for pickup. `` The kid could n't make friends with the natives, or he's just scared and hungry and wants to go home to Daddy's mansion'', Norris thought as his men rowed him to shore in the landing craft. `` Either way, we'll be setting sail for the Bright Side in just a few hours.'' 
 
 They were a few dozen yards from the beach when William called out, `` Extinguish your torches and just follow my voice in. The light hurts our eyes and skin.'' Norris called back, `` No, just get back in your box an we'll come get... wait, did you say'*our*'? You brought natives with you? There is no fucking way I'll let...'' `` Just do it ya pansy-ass!'' another voice called out. It was a familiar voice, one Norris had not heard in 10 years. `` Frank? ``, yelled the Captain. `` I thought you were dead!'' `` Naw, just unconscious. Whoever checked my pulse must have done a shit job. Or they just lied so they would n't have to carry my fat ass back to the ship. I do n't blame them.'' ( Yep, it was Lieutenant Frank Nicols all right. ) `` Now put out your torches and coast on in. We made sandwiches!'' 
 
 Frank and William welcomed Norris and his crew and set them down in the dark on what felt like wicker mats. Norris heard hushed whispers in a weird language slightly behind him, but was assured that they were friendly. Frank told the story of how the natives had found him unconscious after the attack and nursed him back to health. When he recovered some of his strength, he found some matches in his pocket and struck one, only to hear shrieks of pain from the women in the hut that were tending him. They batted his hand away and took the matches from him, but he heard them arguing about something. Sounding rather annoyed, two women left the room, leaving only one inside. She put the matches back in his hand and patted him on the head. He hesitantly struck a second match and looked up to see the eyes ( normal, pretty eyes ) of a smiling girl. 
 
 `` She was smiling because it was the first time she had ever seen anything but pitch black,'' said Frank. `` And the first thing she ever sees is my ugly mug. Poor girl.'' William chimed in, `` You see, while one in ten of our children get Sun Sickness, one in ten of *theirs* is born blind. Only they're not blind! They just have eyes meant for the light.'' `` Yup'', said Frank, `` And since lightning storms are n't a thing over here, the only light they've ever seen is when their hunting parties ran into our expeditions. Just a little torch causes searing pain to them. They thought we were fucking demons!'' 
 
 With the girl acting as a translator, the natives had formed a plan to have a designated village built far away from any others and send their blind there, to live far more functional lives with `` Sir Frank'' teaching them to build and maintain fires. ( He had given himself a nobleman title, figuring that they had no way of knowing. ) `` Nice to meat you, motherfucker,'' a young boy said as Norris was led into the village. `` I see you've taught them English too,'' said Norris. `` Is it true what Sir Frank tells us?'' said the boy. `` Is it true that there is a whole half of the world on the other side of the ocean where the sky is bright all day?'' 
 
 `` It is.'' said Norris. `` And I will show you.'' 
 
 And thus started the Great Exchange, a practice that continues to this day.
