Marty can't stand his older sister Melissa. It’s even difficult to say right away what infuriates her the most - stupid pink T-shirts with rhinestones, the habit of commanding, or the ability to ruin everything with her mere presence. Fortunately, Marty has a safe haven - his own room. You can always hide there and no one will tell you how to behave or shout because of scattered things. Always, but not now. Mom’s business has taken off, and she needs to set up a sewing workshop somewhere. And Marty’s Den is perfect for this! From this day on, the sisters will have to share one room between them. But it seems it will be a complete nightmare...