My sister discovered her doppelganger on the cabin's security cameras. It's been a nightmare ever since.

It's been four months already. Four months since my younger sister, Cathy, moved into this cabin in the mountains, and I've driven up here every weekend to stay a night or two with her. The cabin's a small, cozy place, with two bedrooms and a big backyard that offers a scenic view of the mountains. Cathy's always been someone who keeps to herself, so when she and her boyfriend, David, broke up, she decided to escape all her problems and move into the cabin.<br><br>David wasn't a nice guy, at least to her. He was always cheating on her, and when Cathy confronted him about it, he said he'd change and do anything to keep her; but he only talked the talk. Cathy grew tired of all his lies, so she broke up with him and packed her bags, moving into the cabin. She already owned it, having bought it a few years ago, intending to use it as a vacation home. Now, it's her permanent home.<br><br>I've always been protective of Cathy, even when she was already an adult. When David cheated on her and Cathy told me about it, I was so angry at him I wanted to beat him up. But Cathy didn't want me to do anything, and I understood that. She was already heartbroken, and having her big brother beat up her cheating ex-boyfriend wouldn't have done her much good.<br><br>Things went on as normal for a while after Cathy moved into the cabin. She'd call me once or twice a week, and I'd drive up there every weekend to keep her company. She seemed fine, at least as fine as she could be, and she'd even started seeing a therapist.<br><br>But then, four months ago, Cathy called me in the middle of the night, saying she'd seen something strange. She'd been home alone when she'd seen a figure move in the backyard, and when she saw it again, she'd finally had enough and called the cops. They didn't find anything, and they said maybe she was seeing things in her head and should stop drinking.<br><br>Cathy didn't argue with them, and when they left, she took out her phone and checked the cabin's security cameras. She'd installed those cameras a few weeks ago, saying it'd be better to be safe than sorry. When she opened the app, she saw a figure walking around the backyard. She didn't recognize the figure, and when she zoomed in on it, she let out a terrified scream.<br><br>It was her.<br><br>Cathy was in the living room at the time, and she knew that the person on the camera wasn't her. But it looked exactly like her, with the same face, hair, and clothes. She called me again, and when I asked her why she hadn't called the cops, she said they wouldn't believe her again.<br><br>I drove up there immediately, and when I saw the camera footage, I couldn't believe my eyes. I could barely say anything, and I just sat there on the couch, staring at Cathy's doppelganger as it walked around the cabin. I finally came to my senses and called the cops, and this time, they actually showed up and searched the place.<br><br>They didn't find anything again, and they said that maybe it was a glitch. But Cathy and I knew what we were looking at, and it wasn't a glitch. It was a person who looked exactly like Cathy. I stayed with her for the rest of the night, and when I left the next morning, she called me again and said she'd been seeing the figure almost every day.<br><br>I started staying with Cathy every weekend, and I even installed more security cameras around the cabin. We never saw the figure again, and we started to believe it was a one-time thing. But last weekend, Cathy called me again, and her voice sounded so panicked it scared me. I asked her what was wrong, and she said she'd seen the doppelganger on the camera footage again. But this time, it had been walking around the cabin *while she was home.*<br><br>I drove up there immediately, and when I arrived, Cathy was holed up in her bedroom with the door locked. She barely talked to me, and she kept saying she wanted to move out of the cabin. I calmed her down, and when she finally came out of her room, I asked her to show me the footage. I wanted to see if it was just a glitch or a prank or something.<br><br>Cathy showed me the footage, and when I saw the doppelganger, a chill ran down my spine. The footage showed the doppelganger walking around the cabin, and Cathy's car was in the driveway. I zoomed in on the figure, and it still looked exactly like Cathy. I finally agreed with her that it was time to move out, and I called a realtor to sell the cabin.<br><br>I stayed with Cathy for the rest of the night, and when we woke up the next morning, everything seemed fine. But when I checked the cameras, I saw footage of the doppelganger walking around the cabin. It had come while we were asleep, and I realized that it had been waiting until nighttime to show up. Or at least, it had been waiting until Cathy was home.<br><br>I stayed with Cathy the whole weekend, and we barely left the cabin. We barely even left our bedrooms. When I was about to leave, Cathy approached me and said she'd been thinking. She said she wanted to stay in the cabin and catch the doppelganger in the act. I was so against it, but she insisted.<br><br>We stayed up all night, Cathy in her bedroom and me on the couch in the living room. We took turns checking the cameras, and we were both exhausted. Finally, we fell asleep, Cathy in her room and me on the couch. When I woke up, I didn't see Cathy anywhere, and I started searching the cabin.<br><br>I found her in the backyard, digging a hole. She barely talked to me, and she just kept saying that the doppelganger was gone. I helped her dig a hole, and when we finished, we buried a big bag in it. I asked Cathy what was in the bag, and she just shook her head.<br><br>The next day, I woke up to the sound of the TV blaring in the living room. I got out of bed and went into the living room, and Cathy was sitting on the couch, watching the news. The news anchor was talking about a body that had been found in the forest, and Cathy was crying. I sat next to her on the couch, and we both kept watching as they showed an image of the body.<br><br>It was Cathy.<br><br>I couldn't believe my eyes. The body looked exactly like Cathy. I finally came to my senses and called the cops, and they said they'd found the body in the forest. They said it was Cathy's body, and I was so confused at that point. If Cathy's body was in the forest, then who was sitting next to me on the couch?<br><br>When the cops arrived, I told them that Cathy was still alive, and I took them to the living room. But when we got there, Cathy was gone. They searched the cabin and found Cathy's phone and wallet, but they didn't find Cathy.<br><br>It's been three days already, and I'm still waiting to hear from Cathy. But I know that's not going to happen. The police said they'd found Cathy's body, and they even showed me the body at the morgue. I identified it as Cathy's body, and they said it was likely she'd killed herself. I didn't believe them, and I knew it wasn't Cathy's body.<br><br>I'm staying with a friend right now, and I haven't gone back to the cabin. I won't be going back there again. I'm glad Cathy's finally at peace, and I hope the same for me.<br><br>&#x200B;