Emily and Nancy’s mom just married a new guy Hugh and now his kids Jessie and Rich are moving in with them. Jessie is cool at first, but then she discovers that they have to share a room. I’m not sure why they would stick her in a room with her new stepsister, instead of putting the two actual sisters in the same room. She ends up kicking Emily’s dog Tiger and then yanking the head off her favorite teddy bear. Ok then.
Emily is currently dating Josh, who once dated Nancy. There are a few jokes about how he ditched one sister for the other and it’s pretty clear that Nancy still has feelings for him, but Emily blows it off. During their first dinner together, the girls realize that Hugh is kind of an ass. He makes rude comments about Rich spending all his time locked in his room reading and brags that he never reads. Emily also flashes back to her own dad’s tragic boat accident the previous year.
To top it all off, Hugh is happy that he lives with so many girls because now he doesn’t have to do dishes or laundry. Emily is disgusted by him, but her mom thinks he’s super cute. Emily is less than happy again when Jessie comes out in one of her sweaters and swears up and down that it’s her own sweater. Jessie then sits at her desk and somehow Emily’s huge (17-page) paper was erased. She kind of attacks Jessie and everyone thinks she’s crazy.
On the gross side of things, Emily has a date with Josh. She sees Jessie watching them and starts making out even harder with him. They finally have a good moment together, trying to make an icebox cake together. It turns into a huge whipped cream fight and then Jessie suggests she take the first shower. As soon as Emily steps out of the shower, she discovers that her hair is now orange. Her screaming causes the family to run into the shower and Hugh discovers that someone poured hydrogen peroxide into her shampoo. Would that even work?
Nancy gives her a haircut, to make the color less noticeable. Apparently these girls have never heard of hair dye. Emily goes to a dance with Josh and when she comes home, she finds Tiger laying dead on the floor, stabbed to death. Even worse, someone stuffs the poor dog’s body in her backpack, so she can relive that moment all over again. Emily is convinced that Jessie is trying to ruin her life.
One of the worst moments comes when Emily is in the bathroom at school. She hears someone come in and mess around, then hears the door close. She smells smoke and realizes they set the room on fire and locked her inside. She manages to get out and runs right into Jessie. She gets over it fast enough for the three girls to go to a concert. Unfortunately, someone shoves her down the stairs.
Hugh is out to prove that he’s both the worst father and stepfather in history, by forcing the whole family on a camping trip to South Carolina. They get there late and Hugh makes the girls go out in the dark to look for firewood. Emily notices an old cemetery and then runs off, thinking someone is following her. She falls into an open grave.
Someone hits her with an axe when she tries to climb out and when she looks up, she sees Nancy look down on her. Nancy blames Emily for their dad’s death because apparently she was on the boat with him and survived, while he died. She’s also stressed about the future and what she might do, plus her sister stole her boyfriend. Jessie pops up, knocks Nancy out and saves her stepsister.
Nancy gets shipped off to an asylum, where she can get “help”. Jessie and Emily are completely over it and bonding as sisters. Rich, who keeps reading Stephen King books, is now reading something entirely different. They can’t believe how much he’s changed and everyone giggles together, ending the book.