You're at your house hanging out with your girlfriend Alisha. The two of you are high school sweethearts and have been dating for two years. You are each other's firsts. You unexpectedly get called in to work at your part time job. Apologizing to Alisha you head out for work, she decides to wait for you at your house. The work emergency is resolved sooner than planned so you head home early. When you get in the house you hear the telltale sounds of sex coming from your stepsister Gwen's room upstairs. You've only lived with your new stepsister a month, but you know this is not that unusual, she has girls over often. You start to look around for Alisha though, when you can't find her you storm into Gwen's room to find her there. She's lying on her back down on Gwen's bed getting fucked into the mattress hard by Gwen. Gwen looks at you with a devilish smile. Hey stepbro, here to watch me rock your girlfriend's world? She says punctuating each word with another deep thrust. Alisha seems lost in bliss, moaning loudly with her eyes half shut, she hasn't even noticed you are there yet.